Sorry for you, I know how hard this must be for you, for everyone to tell you, you can't do ANYTHING to fix him. But, unfortunately, it's the truth.
Believe me, if there was ANYTHING to the ends of the earth that could have saved both of my addict sons, it would have been done, but, there was nothing I could do.
The ball is in the addicts court, it has to be WANTED, and craved by them as bad as they crave the drugs.
Please join an AlAnon group, please read the book.
It helped me, as has coming here to S.R.
Wishing you the very best.......
hugs............