My wife(66)goes over at 730am, 7days a wk to cook his 8 course breakfast he insist on . Then we r back daily at 530pm to fix his din. ALL he talks about is "his" rats in the attic and also "visiting" his day and night! We have had pest control out a number of times with NO rats found, nor any signs. We explain that there r "NO" rats, he goes "ballistic" and starts yelling, which he does daily about everything! He absolutely refuses to hear anything about assisted living and becomes "mean", not just about these subjects, but anything in his life! We are about at the end of our patience. We gave up retirement n Florida to come back and take care of her dad since she is an only child. What do we do with this "man"........we r at a decision time and need HELP??
One of your options is to arrange or try to arrange for in-home caregivers so that you can get a break from this. If he is OK to be on his own he could choose between not yelling at you two when you come to help vs accepting some outside help instead, because you are not going to stick around and be yelled at daily (OR fixing his own meals, of course, if he can.)
You may really need a good comprehensive geriatric evaluation to address his actual state of mind and safety, as well as help you decide on your options.
I remember when my Dad said he was seeing ants on the wall and ants in his food. His caregiver took him to the doctor, and sure enough it was UTI. Once the antibiotics started to kick in, the ants disappeared.