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@Jaded'n'faded I knew that dad had dementia a good number of years before he was diagnosed, I had even figured out correctly that he had alzheimers. Dads GP also knew that dad had a probable dementia because he phoned me to let me know of his concerns and to ask me to try to get dad to make an appointment, he had got my phone number from dad somehow by some subterfuge. He was also the kindest and most helpful GP I have ever met. I told him that I was aware of dads memory problems and that I would try to get dad to make an appointment but it took another couple of years before I managed to get him there.
We muddled along quite well for a number of years and it was only when dad needed to stop driving that I finally got him an appointment and a diagnosis. The diagnosis made no difference for me or dad other than him being started on donepezil which may or may not have slowed down his dementia. No way of knowing really.
In hindsight I don't think that an earlier diagnosis would have helped dad or me other than giving me definite proof to wave in front of those who were in denial and I doubt if it would have changed their attitudes either.
I agree with
@Shedrech that now is the time to get practicalities done such as POA and all financial matters.
It is scary and you are probably the one who needs most support now so keep posting as this is a very supportive and helpful forum.