Here are some updates. 
Ss23 moved out this year after the continued back and forth with trying to get him to pay 400 monthly to us (DH got him a job as a doorman, he makes 800 weekly and has his own room so we figured he can help). It was always some excuse or other on why he couldn't pay up. He began dating a girl who has her own place (by way of her dad who left it to her under his name for low income housing) and I had husband start to kind of force save for him, because SS23 couldn't save to save his life and I wanted him to save so he can move out. We had him start giving 500 or 600 weekly. That only lasted a few weeks before he asked for his money back. DH told him if he gives him the money, he has to move out because that was his money to move out. DH asked him what he needed it for but he refused to say. DH told him that unless he sees he had a place to go, he wouldn't give him his 2k. Ss23 then texts new girl and asked if he could stay with her and she said "of course". He moved out. 
 

Since he moved out, he barely calls unless he needs something. Most recent thing was a cell phone. We allowed him to use our credit to purchase a new iPhone. He still can't save, I get weekly letters from Chase about his overdrawn account. He says he's working on saving, but he blames his girlfriend and says she smokes 800 worth of marijuana weekly. Apparently she is also a "bottle girl" and makes a lot of money. He never calls to ask for advice or to see how all is going. He only speaks to SS17. 
 

SS17 started his final year of school. Our relationship is still rocky. A part of me feels bad because I know that it all boils down to the fact that they have a toxic mom, and I wish I was nicer and more forgiving. But every time I think Incan get there, something happens. 
 

In September, DH decided to go for another stint on the road. He retired from his doorman position in June and is starting his second career in trucking. I never wanted it to be an on the road thing but it seems this is what it's becoming. I wouldn't have minded as much if SS17 didn't live with me, but he does. Of course, as soon as DH goes on the road, I get a call from SS17's schools that he threatened suicide because a teacher asked him to take his hat off. They said a parent had fo go pick him up from the school and he would have to be cleared by psych before he went back to school. I was on my way to work and had to call out. I picked the kid up and he starts trying to downplay everything, saying they took him laterally, that he was just kidding. I tried explaining to him that he has to stop doing this. That he's about to be 18 and out of school and he can't keep having a chip on his shoulder and treating authority figures like crap. 

He then says he doesn't need anyone to like him, proceeded to be sarcastic with me and say "oh because you have it all figured out", I mean just triggering me. He said a lot more, but by the end of the day, he tried to backtrack and ask me for a hug. I was too angry and told him I wasn't ready for all of that especially after all the things he said. I fantasized about kicking him out again, but my conscience wouldn't allow it. Instead, I reported the events to DH and told him that I didn't know how much more of ss17 I could take. If he's going to continue to be like this as an adult, he can move out. Into a shelter, or I'll just rent my house out and up and leave to a smaller place. I don't want to support a grown man who is mean and rude. I see that with SS23, all we did was wait 4 years for no reason, because it's not like he changed much after graduating. He was selfish, manipulative, smoked all his money away and when he finally got pushed to save to move out, he left and still has the same horrible habits. I won't give Ss17 the same grace period. He either has to work, go to college or go to the military when finishes high school. I refuse for him to be in my house on the internet all day while I go work to pay bills. 
As for DH, I made a discovery this year about myself. I think I used to think he was such a nice guy but I never saw how much of an inconsistent and lazy parent he was and is. It has made my respect for him diminish, though I try to be understanding. His first 2 kids grew up to be selfish, lying, manipulative, crappy people and I get that the power of a toxic mother is strong, but I feel like DH could have helped them if he had been more consistent, if he cared enough to discipline them, if he would have listened to me when I first told him I thought both SSs were screwing up. 
Even now. Even now I tell him he should try to have a man to man with his first son to try to figure out his real why. Why is he so unattached, so uncaring. But DH doesn't seem interested in making that a priority. He says he'll get it one day, life will teach him. I keep wishing for this "family", this "togetherness" of all of of us, where both SSs finally get it and act like we are all family, but nope. Not in the cards for me with them it seems.