I don't think I mentioned before, but my father-in-law suffered from Alzheimer's in the last few years of his life. I actually didn't get a chance to know him before the effects of the disease started to subtly creep in, but I remember very distinctly the first family trip to their summer cottage I went on, where Bill and I faced his father's quiet struggle to cut his meat and his bewilderment when he sometimes lost track of where things were around him. As time went on, I witnessed and to a certain extent shared Bill's grief at how more of his dad seemed to be gone each time we visited. And it was roughest on his mom, of course, caring for a spouse at home who was going through both a physical and a mental deterioration.
Eventually she could no longer handle him on her own and moved him to a nearby facility where he would have 24-hour care. It was sad but at the same time a blessing when he passed away, with Nancy at his side; he had some sort of a seizure one day at lunch and the staff were unable to revive him. We had been to see him not long before, and he still recognized us, though he didn't talk much. The man I had first met had been vibrant, active, cheerful, and smart, and yet Bill told me I never really got to know his dad as he once was.
I took a picture of him one time that I was very pleased with, out in his garden, showing me his tomatoes. If you had just met him then, you might have thought him simple, the disease had progressed that far, and yet while he was talking to me about one of his favorite enthusiasms it brought enough of his real character and energy back into his face and expression that the photo had at least echoes of his old self. So far as I know it is hanging still in Nancy's house.
I could go into more detail, but that seems very personal to Bill and his family, so I'll simply say that if there is a cure, or even just a way to avoid contributing factors, it is very worth finding.