Up all night,
The good news in your post is that they are planning to move away from where you live. I hope that happens, for your sake.
As soon as you can, as others have said: Stop the flow of money.
No more money, no more cars, no more co-signing, no more nothing. Approach him, when you want to, with nothing but your empty hands, open. Nothing but your words of love and encouragement.
Often, when that is all we offer, either they distance themselves and we don't hear from them for a while, they become more abusive or they start to change.
It takes tremendous self-control and self-will. If your husband is the one who "keeps on giving," ask him to read this site, go to an Al-Anon meeting with you or read some literature on codependency. He needs to learn how much he is not only damaging his own future, but that it is not going to change a thing about your son.
The chance for change will come when everybody stops.
That is the hardest lesson of all for us to learn. It sounds like you are already there. And I understand your anger, but as others have said, once you release your anger, there is once again no chance for him to learn something from the silence.
I finally realized that the dance of anger we were doing just prolonged the pattern. Once I stopped, and there was silence and nothing but love and kindness and space and time and distance, he had to start looking inward. He could no longer blame me because I wasn't dancing the dance with him anymore. No partner, and you're just dancing by yourself.
