You should definetly contact her physican who probably is totally unaware of this important information. It could be a serious neurological problem post surgery that needs to be addressed; or it could be the medication she is on to control for seizures.
Oops. Guess I'm not supposed to be posting here. My apologies.
Dear worried,
For your mother's sake, it seems to me that you are duty-bound to contact her physician to discuss her recent personality changes. You could stress the need for confidentiality before discussing any details her. Perhaps she could advise you on how to obtain additional external help from organizations and individuals who specialize in gerontological issues. Good luck to you.
Bob D