Hi there ~
I understand your concerns. Memory loss
at this age is normal and getting a CT scan may show atrophic changes and maybe other organic pathology that might explain the symptoms. It is called dementia and it can be treated with many medications, among them donepezil
and galantamine are popular. However you need to consult a psychiatrist
for the same and also to treat the behavioral changes that he has been experiencing.
I hope this helped and I wish you the very best. Take care!