You are doing the right thing for your own mental health by disconnecting with him. His mental illness can get worse and dangerous. The fact that he indulges in drugs along with being mentally ill makes him even more unpredictable. This is not something you can fix.

When someone is prone to getting psychotic and take medication only to stop taking the medication where they once again risk having psychotic episodes, they put others at risk. Their thoughts start getting delusional and add alcohol or drugs to that is much too dangerous for you or others.