I wouldn't get to down on thinking this is how things will always be. With time and maturity and hopefully someday, the end of his pot smoking, things could change. My difficult child hated doing anything with family. He didn't coldly detatch himself from us, just hated eating with us, doing anywhere with us, etc. but now that he's clean, living on his own and becoming a healthy happy productive part of society, he actually likes to come to dinner and once again partipate in family functions. Your son is still very young and has many decisions to make in his life. I think he's still trying to test you and see how long you will actually allow him to not be involved with the family as long as he's following the rules. He probably feels if he treats you this way long enough, you won't be able to stand it and you will be the one giving in. Prove him wrong and eventually he will be the one who won't be able to stand it and will come crawling back to you guys. I can almost guarantee it. He's still playing the game and wondering who's going to win.
You and wife have come very far. Keep it going. You are both doing great!!