A.M.
It does have red flags of dementia and/or Alzheimers...
Anger is my grandpa's worst part of Alzheimers. It can be very rough and when they take that anger out on those they love the most it is even more difficult.
Only her doctor can diagnose her though...Does she have children? Anyone that can convince her to go to the doctor? I would take her immediately to have her looked at. It could be a number of things. Are there any other symptons.
Go to http://www.alz.org/alzheimers_disease_know_the_10_signs.asp