Welcome back...there's always a warm seat here for you.
I have to agree with the others in that YOU can not develop a support system for him and his family is not the primary reason for using.
He uses because he's a drug addict...period. And the longer you buy into his rationale, the more comfortable he will be in continuing his use.
When I learned that my son was addicted, I blamed everyone and everything...except him. I now know that one of the most life changing realizations for me was the simple aspect of acceptance.
Once I honestly accepted the fact that my son was addicted, and what addicts do, and that there never may be an answer as to why...I was able to think more clearly and begin to work on my own happiness.
I have never stopped loving him for so much as a minute...but I understand a bit better now.
I return often to that acceptance when I need to get back on track.
(((Hugs)))