What's the name of the medicine used to help with memory loss?

I thought that I saw online here that there is a medicine used to help with memory loss. I recently heard of coconut oil being used. After not seeing my FIL for nearly 6 months I was shocked when I did see him. He had a blank look on his face, did not initiate any conversation, participated very little in conversations going on around him, he says that he doesn't read much anymore and he naps a lot now. When I got home I called my BIL and he said that FIL repeats himself several times in an hour on days that he is talking, he stopped taking long walks like he always did everyday, he does not drive much, and that he admits that he is having memory problems. My MIL is too close to see the changes I saw to a certain extent but I know what I saw. My mother has really bad memory problems and from what I understood from her Dr. is that he could not do a brain scan to see if her condition is Alzheimer's but most likely he said that it was from plaque blocking the memory pathways. My mother hid her problem for quite a few years before I was able to piece everything together and get her to the Drs. to be diagnosed. I want to be able to guide my MIL in the right direction to get help.