It seems heartbreaking to tell them. But she's at the point other people are noticing the little things that say 'dementia'. I have to make some decisions for her as she's incapable now.
I feel like putting it out there will hurt. But it may make it easier for her to let me help her.
Should I wait and have her physician tell her?
If she is too far gone, then she might not remember that she has dementia after you tell her. It may just cause her pain at the moment you tell her. After that, she may just forget.
My dad still tells people that I am an effing liar because I got caught in the trap of telling him to save the doctor the discomfort or whatever his cowardly hide was worried about. Had I known what the fallout is I would never have said a word.