He has undiagnosed dementia of some kind. We will not put him through a CT scan and he is under wonderful care from a geriatric group of doctors.
Goodness, he is suffering such indignities and sadly is still very aware of them. His body and mind seem to be failing at the same time. Incontinent, forgetful 24/7, is struggling with forming sentences, can't walk, makes bad decisions (forgets he can't walk and falls), etc. Typical dementia behaviors. He has NO quality of life other than having amazing care where he lives. MIL lives there too and is flabbergasted at all the changes and spends all day correcting his speech, his flawed memories ("No, we can't go home, we live here now!"). She cannot be convinced to just leave him be. She's suffering too, as he is not the person she once knew. He's sick and is not going to get better. He's nearly 90 and she's 88.
Once a wicked smart and vibrant man, now is reduced to this and he knows it. :(
Perhaps he doesn't understand her, and that would literally be a blessing since she seems to be quite lacking in knowledge about dementia.
I wouldn't consider feeling the way you do about his dying in his sleep cause for guilt, although I know and realistically can't say that I wouldn't feel the same way. He would be relieved of so much trauma, which he's apparently experiencing in a variety of ways now. When there's no progress and no hope, you look to comfort, and a nagging wife isn't going to provide that.
Another thing you might ask a SW or staff is to speak with her about limiting her visits, so he can at least have some down time inbetween lectures.
I think that any caring person who sees someone suffering, w/o relief in sight, is focused on the relief of pain, suffering, agony, and other challenging end of life situations, and that's part of being a compassionate human being.