jolieblonde, your story is a very familiar one to me and i really wish researchers would study these issues, but research is directed by drug companies and they want the one-fits-all easy pill to prescribe. too bad.
dementia is scary for the person and therefore when pushed to do things, often that person resists or even gets very angry and these are reactive to caregiver approach, as opposed to mental illness.
suggestions often work better, as in ,"honey, here's your pills the doctor gave you," rather than "i want you to take your pills."
with food, i put it on a plate in small helpings, as colorful and attractive as possibleand possibly in more frequent little meals than three big ones. then just offer, as in "here we are, honey." and back off.
this prevents confrontation and can sometimes help. i find often people will eat what's there who might refuse a question, "would you like some of this?"
i hope your husband had a full alzheimer's workup (without which alzheimer's cannot possibly be diagnosed)and also a consultation with a psychiatrist. (that conversation while asleep is something not typical to alzheimer's -- a few words, yes, but a whole conversation, rare).
so it suggests he might possibly be having other issues, maybe seizures while asleep? i don't know. i'm no doctor. i just have dementia experience to know what "normal" dementia looks like. when it doesn't seem usual, i think further expert attention is a great thing.
and his family history, with the longterm personal isolation also might suggest mental health issues, which can still be helped. it's not too late for him to experience peace in his life.
a friend of mine finally managed to get her deeply troubled and troublesome 82-year-old Mom seen by a psychiatrist (not a neurologist). he diagnosed her with "life-long undiagnosed bipolar disorder".
since then, she has been on bipolar medication which , as my friend says, "has given me back a Mom i never even had before." not drugged up, but a calmer more relational being who can actually talk, laugh and show affection -- things never seen before. she's no longer tormented from within.
so it's worth the extra trouble of pushing for a more exact diagnosis if things don't seem to fit right. don't be shy about insisting. a referral is your health policy right. note down some of those issues, whether life habits or present issues to help the psychiatrist have a fuller picture of your husband's life.
believe me, it might help your whole family. best wishes and good luck with all this!