I think all of us who care for a person living with dementia can relate to your post groovy.
I was just now looking through my wife's last filofax because I needed her national insurance number. She used the filofax very successfully for a few years to help her keep organised and to remind her of things she needed/wanted to be able to remember. I didn't find the NI number there, but I did find all sorts of details that she'd jotted down over the years (we replaced the dairy pages each year in the leather case but kept all the other pages). The handwriting ranges from normal (she had lovely handwriting) to scrawls that were very hard to decipher and often contained repeated letter and syllables.
Amongst the things she wanted to remember are family birthdays then (later) family names, her daughters' favourite animals, places where she lived and worked, etc. I read these with tears in my eyes (I'm crying now).
Perhaps the most moving notes are references to her youthful travelling adventures. At the age of 18 she did VSO in Ethiopia and was introduced to Emperor Haile Selassie! She also drove coaches overland to the Soviet Union.
Now, needless to say, she cannot drive, read or write, and her conversation is very limited. But, perhaps because of her personal history, she still gets some pleasure from travel, despite all the difficulties she has to overcome.
You can look back at the earlier phases. Difficult as they were to come to terms with at the time, you would give anything to be back there now.
Of course, we are both lucky. My wife is generally calm and contented. She is physically healthy. I am deeply affected by some of the posts I read on TP, from people who are not so fortunate.
But, for all of us, it's a horrible disease and, yes, to see aspects of the person disappearing is perhaps the hardest things.
I wish you strength Groovy.