HI, welcome to HCM
First of all please remember your gradma is 91 yrs old. Senile dementia
is a condition in which person start to loose his memory as age advances. Than gradually loose his/her daily activity also.
Also she is having loss of neurons additional to age related loss of brain volume.
I will also want to tell brain tissue is not pain sensitive so this scar will not cause pain.
All complaint are due to her old age and chnages in her memory.
So just take care of your grandma and keep her happy.