My parents and I bumped into my sister's sister-in-law a week or so ago at a local restaurant. My mum, apart from having Alzheimer's, has had a right old year of poor health, and the sister-in-law asked her how she was doing, how she was looking really well now, the usual sort of enquiry. My mum dutifully answered the questions, and we all went to our respective tables for lunch. I would add that my mother has known the sister-in-law for twenty years. After a few minutes, Mother turned to me and said, "Who was that and how do I know her?" and my father and I were incapable of speech for several minutes! We also find that she has lost all her capacity for being tactful, and can be brutally honest about someone's appearance, or how they speak or whatever, which can sometimes be cringe-making!!