He sounds depressed. When did he start using weed? What’s happened to his friends? Transitions are incredibly hard for anyone but having to kick start adult life when you have gone off track can feel incredibly challenging.
Leaving school removes all of the structure from a young man’s life and requires him to create his own structures and routines. Often our kids have no experience at this and struggle to know where to start. Without friends to cheer him along it’s going to be even harder.
i would suggest beginning by empathising with him. Talk to him about how hard it must feel to leave school and all the routine that provides and discuss with him how important it is that he has dreams for his future l. Try to brainstorm any thing that might interest him.
The first thing he needs to sort out is his sleep/wake routine, because without a consistent routine he will have no foundation in which to build.
Empathise with his position, but also make it clear that you will hold him accountable. He has to have a plan each week, and stick to it. He also either has to be in training, education or employment. Where is he getting his money? You will have levers over him, but it’s much better to start by using connection rather than try to use power.
i interviewed Ken Rabow about failure to launch and he was really helpful on this topic. Look him up.