You will likely go through a lot of caregivers; they will stay for X amount of time and then decide to quit b/c it's too much to deal with, a combative & verbally abusive man to care for. The best thing you can do is get him properly medicated, as suggested. For his OWN sake as much as for everyone else's sake. His behavior is indicative of agitation and warrants medication to calm him down. My mother had good results with low dose Ativan administered every 8 hours and then more frequently as needed when her aggression got worse.
Wow, does Ativan work better than seroquel? I'm open to anything. My dad has been on seroquel, and the neurologist told us at the dose he prescribed, we could give him up to 3 a day. He kind of fell off a cliff a few weeks ago, and has become a total uncooperative, physically violent BEAST when trying to get him out of bed just to start the day, getting his pullups changed... even getting him to take his dentures out to clean them at night... trying to deal with toileting, showering, hygiene in general has become borderline impossible. I just finished answering a post discussing how dementia doesn't change a person's core personality, but I believe that after a point, it sure does. This warrants a trip back to the neurologist, that's for sure.
Good luck.