My mother (89) does not have dementia. Yet. But I have noticed what seem like early symptoms, especially when I compare her capabilities from just a few years ago to now. For example, I recently pull out a document she wrote for me in 2016 outlining things she wants me to do when she dies. She could not even approach such a project today. Also, a couple years ago she came over to cook dinner. I showed her how to start the oven, which she did by herself without a problem. Just yesterday she wanted to cook a frozen pizza. I showed her again how to start the (same) oven. It's a simple sequence of 3 buttons, but she became confused after button #1. Her decline has been steady, but seems to have accelerated since she fell and broke her hip in August. Even friends have noticed.
On the other hand, there are many things she can still do very well. She still balances her check book, (although I'm finding out she did not have a clear idea of her monthly income and other assets.) She organizes and remembers her meds. She can even list them and recite what she is taking (although with a little more hesitation than a few years ago). She cooks. In public and social situations she is very good. If you were to meet her you'd probably think I'm crazy to be worried about this, and maybe I am. Anyway I don't think it is serious right now. But I'm sure that should it become serious, I would not know how to approach the subject with Mom. She would deny it and say she was just getting old. She would never in a million years agree to a dementia examination. I don't want to jump the gun on this, and would not even bring up the subject now, but when/if the time comes, how should I (or should I) approach the subject?
As far as your Mom is concerned it does sound as though she does have some dementia. I think all you can do at this point is make sure she is safe, like not driving or climbing ladders and she continues to manage her finances etc.
A major event like a broken hip and the subsequent surgery often accelerates any kind of cognative deficit although there can be a lot of recovery. She is 86 that was a big blow.
Thanks for your suggestions.