Should this person be allowed to drive or not?

My mother-n-law has been doomed with 2nd stage A.D disease.Sorry the spell check would not help with that word. I have known for a while, but no one wanted to believe me, so I had to prove this by getting her an MRI of her brain. It was conclusive to my therory. She is now on the best treatment available for her condition, but should she drive? To add to this, now she has beginning stages of caterax too. Her Doctor kind of told her, but really left it up to her and the family. I vote no, but I am just the daughter-n-law, I don't count, even though I am the one taking care of more of her things to make sure sure doesn't fall behind!!