He NEEDS detox before any recovery is possible, but you can't force him if he's not interested. And I wouldn't make any "deals" if I were you--like "you can come home once you've detoxed and get sober in AA." That's what you've BEEN doing, and it isn't working for you, is it?
I think if I were you, I'd want to see a good long stretch of sobriety before letting him come back. Rehab followed by sober living arrangements. The point is that he can't indulge his addiction in YOUR home, and disrupt the lives of YOU and YOUR kids any longer.
Your decision, but I think that's what I would do. Then step back and let him decide what he's going to do. But don't give him too long to think about it. Trust me, he will tug at your heartstrings and give you a zillion excuses and promises. The promises are great, but he's going to have to start fulfilling them somewhere OTHER than under your roof.