Dementia can be a horrible ordeal. My wife's mother had it and died with it, her father seems to be starting that way, although with him it is hard to tell. I did hear an interview with a man who had Alzheimer's and was quite content being in the present, realizing he was not his memories. Quite enlightened. Each encounter was a new encounter.

From a spiritual standpoint I see it as a Bardo, a transition period where the personality is going through this mental landscape, with all subconscious tendencies coming to the fore. According to Tibetan Buddhism, this is what we go through when we die--our minds become naked. That is why it is important to practice to prepare and come to the realization that it is only the mind.

There are lots of studies about preventing the possibility of dementia, which is basically keep using the mind in positive ways. If you don't use it, you lose it.

I am glad you came to the point of freedom in being able to forgive him--for he knew not what he had done. Of course, ultimately, until one realizes their Self, that can be said of everyone.

Cheers, my friend.❤️🙏