This is all so familiar. OSD was 15 when she first went through her phase of threatening suicide any time she wasn't getting her way. This may not be much comfort to you now, but it was a rollercoaster for a few years. She hated us, everything was our fault, blah blah blah. Her therapist (chosen by BM, of course) was also extremely inexperienced and did a LOT of damage by supporting BM's alienation. It wasn't until OSD went into an inpatient facility at 18 after a halfhearted suicide attempt that she actually saw a qualified therapist who was worth a damn. At that time she was prescribed a mood stabilizer and an antidepressant. It took a bit to get dosages sorted out, and there have been ups and downs, but now she's 20 and it's like she's a completely different human.

When it all started, I genuinely believed that our relationship with her was going to be damaged beyond repair because the things she said and the things she claimed to believe were so completely unhinged that I just couldn't fathom that we could come back from it. But we did, and she's truly a delight to have around. Her relationship with BM is very, very strained because she's started to put together how BM manipulated her and she obviously doesn't appreciate it.

All that to say, I know how painful it is when the situation seems so hopeless and final. But maybe there is still hope that your SD will mature and get the right kind of help for whatever she's going through. 

Oh my goodness lady, I feel for you. I have no words other than I am so sorry you are dealing with this. Being a step-parent can be so thankless and NOT rewarding, not even a little.

Definitely not that I would ever want it to happen in this dramatic ridiculous way but man, if I could get SD out of my home for 4 weeks straight I think I would be so happy! Lol, okay that was horrible to say, sorry not sorry. Ha!

This sounds like Spawn; except we had custody and it got to a point where no matter what we said or did Meth Mouth was the savior and we were the villains.  DH allowed Spawn to move in with her maternal grandmother her senior year because things had gotten so toxic. I would like to say they get better, but they don’t. DH has been estranged from Spawn for all her adult life, except for a few instances where she reached out to him and met up with him to blame him all over again for everything and to tell him what a saint Meth Mouth is. Your SDs counselor is toxic, and your DH should report her to her board or something.

She got what she wanted but I think she expects him to cater to her needs, bring her food, give her rides, buy her things to prove his love. 

I suggest a simple "no" every time she asks. She claims to hate him, she has to hate all of him, including his wallet. 

the same goes for her mommy. 

and if you hear word one of a suicide threat, she needs to be taken to the hospital. Let her and her wackadoodle mommy know that suicide threats are real and will be treated as such. 

I would also file a complaint with the director of the counselors work place. that is not professional advice and her crying shows me she is not suited for the job.

Crazy and DH. who IMHO. Spends way too much time and head space with crazy.  Can't handle SD.  Because of there fighting it's give SD a opening .. To play them against each other.  
You did not make the BM ..DH marrage or divorce....  You did not make SD or make SD behave in this way.  You will not Babysit SD.   As Crazy and DH, wash there hands  of the work. SD needs.   DH and BM are not working together, to solve anything.  One should change there job or hours to be free in the day time as normal people do it.  

My OSD20 was PAS'd around age 13 and has estranged herself to this day.

Not all kids are successfully PAS'd. It does take a specific personality to do so (YSD17 I would say is "partially PAS'd" but not all the way because she's less bent to other's influences). My OSD was always not a very nice kid, knew how to get what she wanted, played both parents, was the "ringleader" of her friend group and was a bully (confirmed to me by another parent) even though she complained herself about being bullied. She wanted to be catered to and entertained all the time.

Well, as she became a young teen DH had about enough as her attitude became worse at our home (and through some accounts BMs). BM let her have her way all.the.time. DH, while not insituting firm ground rules and still wishy-washy came down on her about attitude and entitlement (too late IMHO) and she went running every time to BM. She'd cry to BM on the phone for hours when she was here and didn't like what DH was doing, or likely me. I think she filmed us and she also texted BM. BM became her 'best friend' during this time.

DH had many convos with BM, some of which I overheard, and it was appaling. BM would believe a 13 yo's story all the time, over the adult, DH. Nothing DH said, explained, or had proof of was believed by BM. We just had to be nice to OSD and do what she wanted. Um, no. OSD eventually started refusing to come to our house because she was mad at DH or scared of DH or whatever excuse there was. BM supported her, at 13, decision to not come. Because it was so hard on her. BM does not respect, like or support DH as a father figure whatsoever. He's not important. He can be ignored and that certainly was instilled in OSD, and to some extent, to YSD.

After OSD refused to come to our home, counselling was tried. And failed - BM "could not get OSD then 14 to go." This was to a highly respected therapist who had PAS experience. BM suggested just bringing YSD. DH said no. We found out later OSD did see a therapist herself who supported everything OSD said (DH had one meeting with her and nearly walked out) regardless, again, of the other adult.

There were two in person meetups with OSD since then. A dinner with all of us (me, BM, DH, YSD and OSD); note I initially refused because it was supposed to be at BMs home - um, NO. OSD came out as "bi" to us there. We literally shrugged and said "ok." After dinner, after not speaking much at all to DH and nothing to me, OSD literally RAN out of the restaurant to the car yelling at BM to unlock it like she was trying to get away from DH. The next meeting was with DH and OSD along with a "neutral party" (Laughable because it turned out to be BMs best friend) OSD set a 15 minute timer on the table (I think she was 15 now and hadn't seen DH for a year???). She wouldn't listen at all to DH, ignored his proof that he had tried to contact her, talked down to him, swore at him, and then ended the meeting. It was a disaster. DH thinks she had it planned out.

After THAT DH decided to take both SDs on a week long trip to europe with us. Completely against my wishes. This is in my blogs. He thought it would reconcile the break. NOPE. Not a word of thanks to him and cut ties again when we got back.

Two years pass and she's 17 applying for college. DH refuses to provide a money commitment when BM, not OSD, asks for one because he knows nothing. Not what schools she's applying to, her plans, what funding she does have already (BM and her father have the $$), what about the no contact thing and no, he refused to pay until he can have a discussion about it with OSD. Well, after some time, this does happen over the phone - again, disaster. She quickly begins yelling and swearing at him because he won't simply open his wallet - in fact, he does say something like "I'm not just a wallet." She hangs up on him after yelling "You are destroying my college dreams!" Whatever.

To this day they haven't spoken, so around 3 years now.

DH got himself a counselor, which has helped. He still sends birthday and xmas gifts (no thanks of course). He has tried to contact her but he becomes very upset at no response although I tell him don't expect one and keep doing it. She has blocked me. She hates my guts too (per my sis in law who also knows our sitution and also has a nightmare of a SS and SD situation) and stopped talking with me before DH. He still gets into funks and I have to make it clear to him when he lashes out at ME than I cannot help him or resolve it for him. He still desperately wants resolution, which cannot happen unless OSD also wants it. I listen, I give general responses (I'm sorry, that's terrible, I see, etc.).  It will not end, it is also called ambiguous loss or something like that. Estrangement is the worst. It doesn't end.

I highly suggest your DH stick to your household's expectations. And give SD space. I would recommend your DH contact her and tell her that he will agree to her terms of the temporary break which are (then list them). If her birthday or holiday falls during it, he should send a card or small gift or something. Nothing extravagent. Keep all copies of DH's contacts. She will need them some day. Expect anything sent to BMs to be intercepted by BM. Expect BM to be listening to phone calls and reading texts. If possible, find a personal counslor for DH. Support him, listen and have empathy (which you certainly do).

I can't speak to our own experience with alienation. We are definitely facing it, but SS11 is caught in loyalty binds. He loves all of us; BM, GF, DH, and I, but doesn't want to upset BM and GF by loving us. He will do/say anything to make BM happy and prevent himself from dealing with her silent treatment or emotionally manipulative punishments. SS doesn't view DH and I as parental figures; we are more like aunt/uncle and BM and GF are the parents. He holds their opinions, rules, etc. above anything we decide. He still is polite to us and enjoys spending time with us, but there is a significant difference between the relationships between BM and GF and SS and SS with us. They are home and we are visiting a relative. 

My grandpa, however, experienced alienation with his two kids - DD and DS. He was married to his ex, who was unemployed, low educated, and lived off of the system. My grandpa had every other weekend visitation, split holidays, and a whole month in the summer. He paid very hefty child support since he was a doctor. The kids were 3 and 5 when the divorce took place. My grandma and grandpa both said that the kids were always terrible during visits, blaming them for everything, yelling/emotional, etc. Things only escalated when the kids got older. My grandpa said there was one weekend that DS screamed at him and told him "I never want to see you again!" and Grandpa was so frustrated with his behavior and forcing a terrible relationship that he said "Fine! Don't. If you don't want to be here, I won't make you." DS pulled down his pants at 12 years old and defecated on the foyer floor and my grandpa immediately drove him home to BM. When DS got back to BM's, DS lied and told BM that grandpa drove him to the court house and filed for full custody. BM freaked out on my grandpa, who explained how illogical that is, given that BM would have received a court summonce or FOC documentation had he filed anything. He basically explained to BM and both kids that he isn't playing this game and if the kids hated him so much, so be it, he would leave them alone.

That was the last time he saw his kids before high school graduation. He tried reaching out, but either BM blocked it or it was unproductive with the kids. My grandpa attended their high school graduation and all DS could say was "Do you have a check for me?" My grandpa cut all contact after that. His son died at 38 years old of a heart condition, never reaching out again prior to his death. My grandpa's ex mailed him the obituary with a note that said "You would have loved him" as if my grandpa ever had that choice. My grandpa mailed his daughter a letter after his son's death (about 10 years ago) and she reached out to "rebuild the relationship" which turned into visiting once a year to use my grandparents' house as a vacation destination and ask for money from him. Even in her mid-40s, she refuses to be accountable for her own actions that contributed to the failure of their relationship and continues to blame Daddy for everything. She believes he "owes" her and paying for his mistake of "not fighting for her" forever is the only restitution possible (even though she doesn't think that is even enough). She never called for birthdays, Father's Day, to check in, etc. so he started distancing himself again. My grandma faced multiple life threatening episodes of sepsis over the last 10 years and one year, his daughter bitched to my grandpa about the fact that her kids didn't get enough Christmas presents from them that year (despite the fact my grandma was on her deathbed the whole month of December that year). When my grandma died last year, she never reached out, never attended the funeral, and never checked in on him afterward. My grandma's birthday recently passed and instead of calling her Dad to see how he was doing, given it was the first birthday since grandma passed, she took to FB to post about how much she loved and missed her dearly departed BM and how BM did everything for her. He told us recently that he is done with her and took her out of the will. 

In instances like yours or my grandpa's, I don't see these situations getting better. I see kids seeking the paths of least resistance despite what is good for them. They want the fun parent with no rules or responsibilities or the parent that buys their bullshit. SD is going to side with BM because BM makes this suicidal ideation thing easy; she doesn't ask too many questions and isn't doing anything, allowing SD to live and relish in her victimhood. You and DH on the otherhand are doing everything right and trying to "fix" her which is the opposite of what SD wants. SD wants to be the victim. You are right, SD will likely grow up to be a loser like BM and their family. You and DH have to find peace knowing you did everything you could and there was no stopping this outcome.