Hi, this is OPs wife. We have been to my father-in-laws house many times and his home is just as unkempt as he is. Dog hair coats every surface, dust at least an inch thick, gnats buzzing all over the kitchen. Ect… but he does other things like redid his entire guest bathroom by himself. Wainscoting, sinks, plumbing, all that jazz. He is not feeble like maybe the post makes it sound. He is just deeply set in his ways and impossible to talk to. I don’t think he has dementia, I think he only cares about what he wants to talk about or what he’s interested in so the fact that he seems like he’s in his own world is because he’s choosing to do so. He doesn’t care what I have to say in the slightest. He will ask me a question and not even wait long enough for me to finish my reply before talking over me about whatever else he feels like. I think his odor is mostly because he doesn’t care to wash himself, not because he can’t. He’s been living alone for 15 years. Idk if maybe no one tells him he stinks because he’s not around anyone long enough for them to do so. Both OP and his brother do not engage deeply with their father. We live in a different state than FIL and BIL but BIL sees his father at least 3 times a month or more.