I agree with everybody else. You´re gonna burn out soon due to exhaustion and then where will you and the kids be? Everybody, it seems, is depending on you!
I think I´d have a nervous breakdown if I were leading your life indefinately. I mean, what is your alternative? How long do you think you can carry on as you are??
He def sounds depressed. The sleeping during the day is a classic sign. He can totally withdraw and avoid you all and life in general. Obv anyone who experiences sleep disturbance would deal with it in various ways, even if this means getting some sleeping pills as a temporary measure. I find melatonin supplements very beneficial. Has he even gone to the Drs about his sleep?
Cos, as prev mentioned, he seems to do a chuffing good job of sleeping during the day! Or is he up and down to the loo then too? Is it cos sleeping in the same bed affects his sleep? Is there a spare bed, or get separate duvets? He is def capable of more than he´s doing but he´s choosing not to. Even if he is very limited in what he can do. But to not partake in family life at all and effectively opt-out of his marriage and kids growing up......
I think he´s depressed, he´s resigned himself to his condition and has chosen the self-pitying route rather than the ¨Fuck this, I´m not gonna let this condition beat me and dictate who I am!¨ route. No matter how ill, people always have options. They can give in or they can fight it and live their lives to the best of their abilities. That´s why I think it´s more psychological with your OH than his illness making him how he is.
It´s now got to the stage where he´s bitter, spiteful, resentful, accusatory etc etc....I don´t blame you for finding it bloody difficult when you´ve been together so long. Maybe you feel disloyal? From age 16yrs he´s all you´ve known! But if you seriously can´t say it to him ( even with a glass of vino for Dutch courage on board?) maybe write an email/letter with your feelings and thoughts, a real outpouring of honesty?
But one way or another, he´s gonna have to be told. Maybe the ultimatum will give him a kick up the pants and he´ll realise just what it is he stands to lose and he´ll fight for it? But for your own health and sanity you need to let him know your thoughts and feelings exactly. Nobody can do it for you unfortunately. 