Does Coffee Helps Slowdown Alzheimer?

I read an article that coffee is good for your health especially on old people who are worried about Alzheimer or even dementia. Even though, I don't drink coffee for religious reason, I still feel that coffee can help my parents slow the development of the two diseases when they drink coffee at least 2 cps a day. I was just wondering whether superior coffee would be a better choice. Or it really doesn't matter whether it is mild or strong. I don't really know. I think, I need to do more research on this one. For the meantime, my folks need to drink mild coffee just to be on the safe side. I don't want them to get lack of sleep because of the caffeine, you know!