FMIL Inviting Wedding Guest

TW: Involves substance abuse and mental illness. Also, I understand this situation is no one’s fault, but I feel it is FMIL responsibility. I have a lot of empathy for all parties involved and understand how hard this is.

FDH and I are getting married in September in another state where neither family lives (essentially a destination wedding). I sent out the Save the Dates in December/early January. FMIL had me send a date to good ‘friend’ of hers, insisting she wouldn’t come but that she would be ‘crushed’ to not get a save the date. As of this time, good friend (will be referred to as Amber from here on out) still had her decades long drinking problem, but for all intents and purposes, was normal and well from what FDH and I understood.

Since the save-the-date, Amber has gone off the rails. It must be understood that Amber has MONEY. Not just money, but big time money. When her mental state started to disintegrate, she would buy new houses, new TVs, new cars, new anything. It got so bad that scum of the earth realized it and would say, “Hey Amber, I’m in trouble and need 5k,” and Amber would go get her check book. This woman has/had the heart of gold, but between her decades of drinking and her mental state, she is totally gone.

They ended up putting her in rehab about two months ago, to which she was diagnosed with Schizophrenia on top of her addiction issue. She was only there for two weeks when Amber called her husband and complained and he picked her up early, further worsening the issues. FMIL insisted over the phone that Amber was doing much better, but when we went down for the 4th and Amber came over to the house, I told FMIL that if this is better I do not want to see worse. Amber weighs about 75 pounds, is talking off the wall sh**, rolling around in the grass, gathering garbage and handing it to people and then also inappropriately jumping and straddling FDH for almost 5 minutes. She is not well and it is very sad.

That being said, I never sent Amber’s actual invitation when she was carted off to rehab. When we were down there, she was telling me how forward she is looking to the wedding. Also remember, she has infinite funds to get there. FDH and I are on the same page that, in her current state, she cannot come to this wedding. It is a small wedding to begin with (less than 60 people) and I think her coming is setting her up for failure and us for embarrassment (don’t come at me for saying that, it’s true).

FDH and I called FMIL and said we need to make a plan for Amber and how FMIL is going to talk to her, to which FMIL said, “I’m not getting involved, whatever you all do I’ll back you," and when pushed further, she said, "I'm not talking about this, I'm not involved," stonewalled us and hung up the phone. Is it just me or is this FMIL’s responsibility? She was the one who insisted on me sending a save-the-date and it is also her friend. It is clear FMIL is not going to be an adult or a good friend and is pawning it off on FDH and I, so with that being said, does anyone have any suggestions? I personally think it’s super rude to just not send an invitation without a conversation after sending a save-the-date, but is that the best option here? You would like FMIL would want to use this as an opportunity to talk to her friend and encourage her to get the help she needs, but instead, she is selfishly putting her own feelings ahead of both her friend’s well-being and our wedding.

Help!