Have the muscle twitches started since starting to taper? That may be a withdrawal tardive dyskinesia which might get worse if he suddenly stops. I find psychiatrists often very cavalier about stopping/changing meds because they don’t deal with the fall out. Although I am assuming you only have your son’s report about what was said so it may be what he wanted to hear. I suppose if that was said it means the psychiatrist believes he may not have another episode.
He would be better waiting until the twitches go away then reducing again. I believe (& have observed) that for some people tapers need to be very slow. We have had massive fall out from my son chopping and changing meds way too quickly.
Could you encourage him to look at a different antipsychotic which might suit him better?
It’s really hard and it sounds like he is going to stop them whatever you say. The right counsellor may be able to work with him to look at other ways to keep his weight down and encourage activity and also to support him to start to notice when his thought processes are going awry. Although I take your point it is very fast. That work prob needs to be done while he is well.
If he doesn’t want that can you talk to him about the consequences for you & how difficult it is when he has an episode. Is his psychosis dangerous for you? If it is you need a safety plan of some sort (which may be 999). Again this needs to be done while he is well.
He may need to come to terms with medication being lifelong for him (or at least long term) but he may need to try again. I can understand why the side effects feel unbearable and you could try and encourage him to talk dose and type of drug with his psychiatrist.
i’n sorry, it’s very hard. You don’t say his age, but at some stage, while he is well you may need to start to discuss his responsibility for managing his illness and for dealing with the consequences (if any) of his decision making. I can understand his desire to try and get off the meds - antipsychotics are horrible drugs, and I fully understand your concerns. It may be that he eventually finds he does need these drugs. But he also has to understand his responsibility for managing it - and recognise the impact on others.
Is there some sort of support group for family members? My son is on antipsychotics for aggression (non-verbal, learning disabled) and I grapple with wishing we’d never started the bloody things but also recognising that unfortunately he seems to need them. We only found that out after a number of attempts to taper. And we met still try and taper off in the future. . It’s hard to find the balance so I do understand your son’s concerns - and also yours - my son’s responses to coming off have been bloody awful so I really do understand your concern.