While he is in the Residential Treatment Center (RTC), start finding what alternatives there are for you. It really sounds like he shouldn't be allowed to come home. It is just too dangerous for you and your other children. Write a parent report giving as much past and present history as possible. If you haven't done so, file a PINS or CHINS petition (Person or Child In Need of Services). Get the courts actively involved. Yes, they're going to try to blame you but stand firm. If you can afford if, hire an attorney rather than using a public defender. Attend local NA or Al-Anon meetings. Get your kids to go as well.
Sadly, I wouldn't even try to save him at this point. He obviously doesn't want help and, if typical, thinks the problem is the world, not him. He is probably one of those people who will have to hit absolute rock bottom before he even considers there is something wrong with his life. That doesn't mean you won't love him, worry about him, want to do everything in your power to help him. It just means that, for now, he is beyond anyone's help. I'm so very, very sorry.