Reading this will rightfully scare the bejeezus out of us. The question is, what can we do? Alzheimer is sometimes referred to as diabetes type 3. Cutting out sugar and eating a low carb diet is a good precaution. It likely wouldn't have helped Jo, but it might save quite a few of us from this scary outcome.
Just because it is referred to that way doesn't mean that it is actually the case.
The hypothesis that AD=Diabetes has been around for at least ten years [1]. If it were true, I would have expected to see some results by now about how diabetes interventions can slow the advance of AD, if not prevent and/or reverse it entirely. AFAICT there have been no such results. That casts the hypothesis into serious doubt IMHO.