My mom died of Alzheimer's disease at 82. She never smoked, drank, became obese, had any cancers, etc. I am quickly coming to the conclusion that whether or not one gets Alzheimer's is a roll of the dice, nothing more.
The latest research is pointing to a genetic connection. (sorry to say that for both of us) A particular genetic configuration leaves one susceptible to degeneration of the myelin sheath (protective covering) on nerve cells in the brain. I have a gut feeling that this is a problem they’re going to find a solution for but I couldn’t put a date on how soon it will happen. I’m sorry you and your mom had to go through that. It’s a nightmare for everyone.