As per yours detail possibility of dementia seems to be very less, but if there is any psychiatrist in your near by area, go for a MMSE to confirm it.

If she has had stroke , she might have some decline in her brain ( cognitive ) functions . She is at risk of developing vascular dementia , she should maintain proper control of her b.p and sugar , if she is hypertensive and diabetic . She should take her stroke medications as well ( aspirin or clopidigrel ) regularly . Keep a healthy life style , regular mild exercise . Can ask her to continue her daily duties . If u could elaborate on what sort of confusion she has , I will b able to help