Sorry about your Mother.
I would do some research on the web regarding the medications she is taking, to see whether they could cause dementia.
Otherwise, you might take her to a neurologist, who specializes in dementia and Alzheimer and see if he has any suggestion to slow down the progression.
I appreciate your comment.
Done - and yes, they can/do.
Already did that a couple of years ago...
If she is on Statin Drugs I would consider taking her off them. New studies are showing just how dangerous they are.