Why can't I help?

My mother is in the early stages of Alzheimers. Last week, she had a fender-bender in a parking lot and fled the scene. This week, we took her to the doctor who told her she was not to drive again. As I expected, she did not take the news well, and indeed, often tells me that I should mind my own business and leave her alone. I'm afraid to even approach her anymore because she often lashes out at me without provocation. Any suggestions I make that would make her life easier and better are met with a snotty response. Now what?