but the vitriol aimed at him is appalling.
I don’t think it’s vitriol. I think it’s exasperation, the rant of someone who doesn’t know what to do next. It’s been three years, I think even the saintliest of people would have started to get frustrated by now.
It's a prime example of how mental illness is such a poor cousin to physical illness. Yes, he might well be displaying antisocial aspects of daily living, but why is that him being 'wrong' rather than a symptom of his illness?
It is different from physical illnesses though. He isn’t physically incapable of washing, he just won’t. Yes, a symptom of mental health illness, but that doesn’t mean anyone around him has to go ‘oh it’s the depression making him and our home stink, I won’t say anything’. There’s a difference between being sympathetic to an illness and letting them fester in it.
I don't know how much he can help his current state, but there's too many people hospitalised because of extreme depression to jump to the conclusion that he is somehow to blame, that he is negligent in his own recovery and that he is at fault.
If their depression is so extreme, they cannot physically function then perhaps hospital care is the best place for them. Obviously, you’d hope there would be professional care before that extreme step, but by literally just eating crap and sleeping, the bloke in question is merely existing. There’s no motivation there to try and recover - anyone knows the basics of feeling good are rest, washing, some exercise and eating moderately well. If you don’t attempt any of these things, just sit waiting for the depression to go away with some pills and parents who do too much for you, then how exactly is he meant to even start to get better? Those who are physically ill have to push themselves at times, so with depression you need to find that push as well.
Does that mean you should continue to have a poor quality of life as a result, of course not, but improving your life and showing him and his condition respect are not mutually exclusive.
Ok, so how can the OP respect her stepsons condition whilst still living her own life, considering the level his illness seems to be affecting her and her husband (who is also ill)? As loving as parents are, most don’t sign up for a nearly-40 year old living at home even when well, it must be bloody tough with an ill one.