Did he just stop or has he been in some sort of recovery program?
If so, he needs to get back at it ASAP!
If not, he needs to start. ASAP!
You can suggest an AA meeting or another 12 step meeting but other than suggesting he reach out and get help BEFORE he relapses there is not much you can do for him.
This is his problem, not yours. It is his decision, not yours.
Hang around and do some more reading. I am glad you found us.