At 24, he may be more willing to listen, than after years and years of hard use. Can you arrange counseling for him and family, to sit down and talk calmly about trying to help him (without enabling) and your concern for him?
In the end, he has to be willing and really want to get clean. If that isn't in place, everything else may just be wasted energy (and money) on your part.
My heart knows your pain and my prayers go out for you and your family.
Hugs