Chocolatchip - I'm sorry for being a bit flippant. My mother had Alzheimers, and would ask after her brother, who had died some months before. I'd tell her, and she'd remember, but would ask again a few minutes later. In the end, I just said he was OK, but it was distressing. The thing is, she was happy, with no bad memories.
I'm lucky in that my wife has considerable geriatric experience, having been a Sister on a geriatric ward (before becoming a midwife). I also have a 20 year old daughter (I'm 71), who keeps me up to the mark.
I've also lived with and cared for alcoholics.
You and your mother need help, and there is some excellent advice here.
The thing from which you may take comfort is that she can be quite happy if you can accept and live with her condition. A memory loss is not done on purpose, and she should not be made to feel guilty. It's a bit like looking after a baby, if you can see it that way.
I've not expressed myself as I would like, but I do feel a lot of sympathy...