My dad died in dementia. "Alzheimer's" had been mentioned for years and he had no idea who I was at the end.
I know the signs and see my doc at least twice a year.
Biden is careful. I am careful. At our age we walk OK, but swagger we don't and we often loose our footing, especially, around uneven ground. My doc assures me this is all age, and he will be the first to tell me when dementia is a concern.
Biden's wit! That's a sign that maybe things have slowed, but the motor still has horsepower. Wit requires and agile, quick response brain. He can still be a brilliant orator as he has shown
Frankly, Reagan was much more down that road than Biden will likely ever be. I believe his illness and it's possible threat to the nation was kept secret deliberately because they had no ay to deal with it.
I owned a home care company for about 10 years, which is why I became a dementia trainer. I certainly spent a lot of time with people afflicted with it at various stages.
Having had the training in it, it made that experience quite enriching. Dementia is a symptom of some 50 different diseases or afflictions (like stroke or being an alcoholic). Dementia is not a function of age. It is ageist to think that dementia comes with age, though those with a proclivity to dementia will generally see it come later in life. Interesting, however, that they are discovering onset of Alzheimer's in younger and younger people (even in their 30s and 40s)
Too many people, including senior care professionals, want to bring those with dementia into reality, which is actually the wrong way to go. You simply can not do that (kind of trying to convince someone that gets their news from ZeroHedge that Trump lost... you just tick them off.) Someone afflcted with dementia may not remember your name, they will always remember how you make them feel. If you argue with them, you are not going to leave them feeling positively about them, and that is one thing they will remember the next time they see you.
As I am from Colorado, I would use the whitewater analogy..... when you interact with someone with moderate to advanced dementia, they are white water, but you have a paddle. If you know how to use your paddle, you can master the river and get where you want. You just can't paddle upstream or just cross the river, so you go with the flow, but steer your boat. Dementia typically affects short-term memory with long-term memories often quite lucid, particularly if you use a little music. I learned to really enjoy being around people with dementia. Many had some great stories that they loved sharing for those with the patience to listen, which of course played into the concept of they remember how you make them feel.
My training came into great personal use when my mom became afflicted. In spite of the training, it still was very hard, because it was my mom (like your dad). I am in my 60s' but two of my best friends are in their 70's. Each is on the regression train with early stage dementia. Again, my training has been helpful here. Anyway, I am sorry that you experienced this with dad. It is a very hard thing to experience with a loved one. It is often called 'the long goodbye.' I am sure you can relate to that phrase.
I have not seen any outward signs of Biden dementia. What he has accomplished in 2+ years in the White House, particularly with NATO and Ukraine tells me his mind is quite sharp. That doesn't mean there isn't any cognitive slowing. He could be an early stage of dementia, we don't know, but he is highly functioning, so its moot. Only 22% of people 85 and older have dementia, with instances of dementia much lower in college graduates and whites. Hence is chances of actually having dementia are quite low. What people are seeing is his natural speech impediment that is likely exaggerated by cognitive slowing (and Fox), which is not dementia. Biden's mental health remains superior to that the TFG, who has quite a set of impairment from other causes.