The symptoms you mention are actually pretty similar to the symptoms of Dementia
or Alzheimer disease. In many cases of dementia, people may show some aggressive behavior because of confabulation they have to cover those lost part of their short memory. When we are suspecious about Dementia, some blood tests like thyroid
function and also B12 serum level should be done, because these are from the reversible causes of dementia. At the end, Dementia could be well controlled with medications which enhance the memory and cognitive ability in the brain. Good luck with your work about grand ma.