My father has become very argumentative and will not listen to my mother when she gives him simple tasks, for example it's time to use the restroom. He has started taking off and walking to nearby malls, buying things that they don't need. The last couple of times he has gone on one of his walks he has ended up in emergency due to falling and hitting his head.
My mother has reached her limit. They live in Canada and have applied for assistance in the way of day care, but it could take 6 months to a year for my father to get in.
Wandering and falling can be serious. Could Mom go for walks with him? She should always carry a cell phone when she does! Maybe if they went to the mall for a cup of coffee and a donut he would be satisfied without buying something. Or they could go to a movie, or visit the pet store, etc.
Exercise, such as walking, is very good for persons with dementia. But falling obviously is not. Is he less apt to fall if someone is with him? Should he be using a walker or cane?
What kinds of doctors has he seen at this point? Has he been diagnosed with dementia? Has he seen a physical therapist? Is he on any medications? Is Mom in touch with any local caregiver support groups?
What other symptoms does Dad have? For example, how is his memory? Does he see things that aren't there? Hear things? Does he have delusions (believing things that aren't true) such as that he is rich or that his wife is an army officer? Does he have trouble with balance? What seems to be causing the falls? Does he have sleep issues? Is he paranoid?
Give us as much detail as you can, and among us we may have some suggestions for you and for Mom.
Your dad repeatedly hitting his head is NOT good for his overall health or dementia, as I'm sure you know. So it's a pretty drastic situation where action needs to be taken to get your mom help, in my opinion.