Like some said, on a scale of 1-10 in dementia he’s at the early onset stages, perhaps 3. No way he lasts 4 years.
Honestly, I think he’s at 5-7. It’s not an exact progression, but he reminds me very much of my mom in her last 2 years. It’s going to get worse, and forget 4 years from now. He’ll be lucky to be alive in 4 years. Unless he has a breakthrough miracle in dementia treatment, this isn’t going to improve. He will get steadily, steadily worse.