Keepinon has expressed the crux of the problem very well. These are issues I have to struggle with too, with my two "mentally ill" children (son is bipolar, daugher has BPD).
In spite of the fact that they have these disorders, they still have to learn to live WITH them. My son has had treatment but chooses to not take any medications now. He knows that he really feels better if he does, but I suspect he'd rather drink and smoke weed. Gratefully, he's at least not mixing medications with these substances. He broke all the rules and got kicked out of our home. He lives with roommates and makes about $1000 a month hauling junk. Yesterday he called and said, "Mom, you gotta help me find another place to live! I hate these roommates and I can't take it anymore." I offered some suggestions (searching craigslist for new roommates, how much apartment he could qualify for, asking his DAD to possibly co-sign, etc.) and then basically wished him luck and said goodbye. I'm sure he thought I would go into full fix-it mode but I didn't . HE has to figure this out. HE might very well be realizing he needs more money and HE might figure out he needs to get back in school (we have $$ set aside for that). Or he may be learning some valuable lessons about how to co-exist with others. Who knows? He's had the experience of being homeless so I don't think he wants that again. He's seen he can't manipulate me into saving the day. Whatever solution he comes to will be his own and when it works out he will be PROUD of himself for getting it figured out. I am very hopeful. He's done it before and he can do it again. None of this would have been possible if we hadn't taken the painful step of kicking him out back when he was 19. If we hadn't done that he'd still be creating chaos in our home. Now whatever chaos he creates, it is his problem to solve.
Just sayin'....