Remove discord from the home if he’s on it.
And encourage him in finding purpose.
Like many boys his age, he’s lost, bored, and searching for meaning.

Help him discover a passion or interest or skill and invest time in building him up to pursue that thing. Take him to a retirement community to meet with a social worker or event planner there and find out how he can connect and be helpful to the elderly. Explain to him that his life is valuable and he can find deeper meaning and purpose in using his gifts and talents to help others. He does have gifts and talents and may just need some guidance in unlocking those and nurturing them.

Depression grows from feeling useless and gazing inward. If all the therapies and counseling services have t made that big of a dent, why not break the cycle and try something new? If he’s busy pursuing greatness and helping others, he may become less interested in nurturing the disease of self that so often consumes young men who are floundering.

Thanks for everyone's responses- yes we made mistakes in letting him smoke when he was younger- it actually seemed to help his mental health for an extended period when he was a casual user. He is definitely self-medicating. He has been on psychiatric meds for awhile and this preceded the drug use.

With his mental health issues he may be trying to self medicate with marijuana. The concern as a parent is the risk of psychosis that is higher than it used to be with pot use and I think a 3x higher risk of schizophrenia. My kid was grounded until he peed clean, almost a month. He could be at school functions, but we dropped him off. He had a friend who od'd and thought he died that he had been hanging out with. That cleaned up those friends pretty quickly. Did tests whenever we asked. He later said he realized that the drug use was not a good idea and interfered with his motivation. His father also talked to him about his life experiences- that may have been helpful. Being firm and caring at the same time is important.