Man, I'm so sorry you have had so much to deal with. Letting go is sometimes the hardest thing in the world.
I'm glad he's in a safe place for now. I sometimes think it's a real shame that our society has made it so difficult to keep people with serious mental disorders in a safe place for their own protection. I'm aware of the arguments on both sides, but it seems to have swung too far on the side of freedom for people to suffer and die.
There really wouldn't have been anything long-term you could do to help him, even if you had temporarily "rescued" him.
Hugs, many,