Life today is HARD, and today's kids have been de-volved by the educational system into whining pansies.
Certainly whatever Watchtower memes he's absorbed haven't helped any.
You have tried the standard catalog of pharmaceutical assistance, but has he tried ketamine? Some researchers have been exploring the value of ketamine treatment, at relatively low doses in a controlled medical environment and they have reported impressive results from ONE TREATMENT; but don't buy "Special-K" on the street and dose him with that. See if there is a study being conducted at a medical center near you.
It is also important that his personal self-esteem is built up, not by chanting slogans into a mirror, but by tangible ACCOMPLISHMENT. What skills or interests does he have that could provide this? I don't think playing computer games counts.