If I learned nothing else on this journey, it's that we can hold out a helping hand, but it's up to them to reach out and grab it.
You were offering him a chance at recovery, a chance to straighten out his life, and he didn't take it. I know you are hurting so bad, but if he's not ready, we can't force them can we? Or maybe by you setting up "no contact" with him, reality will kick him in the head? Only time will tell.
Take care of you....
Eileen