As someone with over 3 decades in recovery, his symptoms sound a lot like like meth psychosis which I have heard of many times from others who experienced it. Some of his symptoms also seem in line with the onset of schizophrenia which often manifests in the mid-20's but please keep in mind, I am not a medical professional and I am not giving a diagnosis-only one possible ideas based off experience. I would suggest talking to a medical professional who deals with addiction and mental illness and lay out the case and symptoms to get their input. I would also suggest contacting an attorney or social worker to see about getting him help which could be a commitment while he is refusing to address his issues. It is long shot (especially in California) but you may have grounds for an involuntary hold at which time they may be able to deal with his issues and get hm to a place where he may consider in patient drug treatment. Again, it is a longshot... Lastly, I would seriously recommend getting in touch with and to start regularly attending a (or several) Al-Anon groups which if fully utilized can be a great source of information and strength for you (and your family).

Best of luck and if you need anyone to talk to, feel free to reach out to me and I will offer what I can within the confines of recovery.