I’m a bit brain-dead atm so can’t find the right words, but do want to say I have some idea of what you’re going through.

My dad had dementia and it took me a while to realise something more than just ‘old age’ was wrong, because I wasn’t spending days with him at a time, and the symptoms come and go.

There could also be other things that might cause unusual symptoms (uti’s for example) so a general checkup to rule things out would be a good idea, if you can get your mum to go.

As others have suggested, keeping records can give you greater insight into what’s happening and when, which might shed some more light on things.