To me, it doesn't sound like his rehab stay was much use to him, as I sure can't see recovery work in the comments and actions you posted.
It seems you are still in the same old bind, only without the drinking this time. Whether he falls or not is up to him, but does it matter whether he is drunk or sober...if the behavior is the same either way?
Going to Alanon and working on yourself are what you CAN do, because it is your business.......working on him is not.