Mom is starting to forget things. Is this dementia?

You need to get a neurological evaluation for your mother. My daughter-in-law had the same situation (down to the 6 year old) and her mother was diagnosed with early on set Alzheimers. They gave her some Aricept and she is doing better, but of course it's Alzheimers and there is no cure. Not yet anyway.

Good luck to you.