All I can say is look to EMI care.
There was a good website ,the carequality commission (used to be csci)which gave a star rating which helped me tremedously (unfortunately,its stopped now) when my dad got too much for his "ordinary"care home.
The gp said it was the dementia,nothing else, gave him seditives and said find an emi.
I did,and it was the change in gps and the medical staff in the emi, who got dad admitted to hospital PDQ.
Kidney failure and cancer (both long standing conditions)agrevated the dementia, the behaviour.The previous gp couldnt see a terminal case in front of him.
This has not had a happy ending,however the proper care he got in the good emi,was so much better than the care he got from the non specialist care home.
The nursing staff and others, were so respectful to mantain his dignity.If he was aggressive they would put him on one-to-one care.It is managable (although it is nursing emi so more expensive,get yourself referred to a social worker for help with costs)
and is the only way to go.
I dont want you thinking that your fathers condition is like my fathers, (eg terminal)but please, elderly mental health is to be taken seriously and you and your mother are not being deficient in looking at nursing homes for your father.
I wished ide moved dad earlier, they would have managed his physical and mental health so much etter.