Does he live with you? Is he dangerous to you? It is certainly a choice that you not help him or enable his terrible behavior. He sounds very out of control.
You can't change him. Only he can change himself. Please focus on taking care of yourself...your mental and physical health and the safety of yourself and anyone else who lives with you, if he is still home. Maybe he should not live there.
Pot is a substance too. He is probably capable of getting addicted to pot or any drug. Too bad he wasn't offered rehab, although for rehab to work, the patient needs to want to quit.
Anxiety and depression are extremely common. I fight both. They don't cause the things your son has done. Drug use can though.
I'm so sorry your son is putting you through this.