It looks like a friendly young man suffers from Clinical Depression. It runs in his family, undiagnosed, he believes. But, his depression is not there for no reason and has never been "solved" by medication or therapy. Something is missing. Insight is fair and there's been plenty of difficulty and drama, including some traumas which provide respectable Post-traumatic Stress Disorder status. Yet, most people with his problems do OK after a tenth of the help he's had.
The nice man has a lot going for him on the surface. Rather than label or medicate him unnecessarily, rather than bombard him with more indepth therapy, how can I help him move on? I hope it's even possible. I just met him and many before me failed.
I have to ask myself why does he hang on to the identity of being so depressed and so sick? What would happen if he felt good about himself and made his life work better or accepted his lot philosophically? Well,there could be some pretty uncomfortable stuff, indeed. He could feel bad about all the wasted time and poor decisions from being dysfunctional in the past if he started seeing that he could feel OK. He could feel legitimately angry about ways his superficially "wonderful" family infantilized him over the years to distract (unconsciously) from their own individual and relationship problems. He could flaggelate himself from protecting them by punishing himself. He could relive his mistakes too much.
Somehow, the best bet will be to help him choose change without too much drama , a little at a time, with a sense of self-respect and some inner peace. I sure hope he helps himself along the way with me, but I can't do it myself.