If I were told that, I would spend all my money or more likely give it to my children rather than them just get what's left when I die having paid (maybe) for years of care.
I'd also set up an Advance Directive so everyone knew exactly what my wishes were when things got bad. I'd make my will and set up LPA.
Sorry if that's not what you wanted to hear.
However... you said 'likely to develop dementia' which is not the same thing as definitely. I have read your other threads and thought about commenting but haven't so far. Whilst I appreciate you are researching dementia and looking for answers, there has always been the problem that dementia can be happening (i.e. changes in the brain) many years before symptoms start to show. You also asked about possible triggers: in my mum's case, the first definite sign I had that something wasn't right was maybe 15 years before she showed other signs. We regularly met up in Manchester and on this occasion mum confused the two main stations and got off the train at the wrong one. She couldn't work out where she was, why I wasn't there or what had gone wrong, blaming the train. I was quite alarmed but it really was a one-off at that point. Gradually over the next few years I noticed small things but really didn't think anything of it. (Well, I did - I started researching dementia and knew years before anyone else that's what was happening. But family were in denial and mum never saw her GP.)
The point I really wanted to make here is that if I had told my mother my concerns she would have told me I was being ridiculous and I expect anyone who knew her would agree. The signs were so small at first. Everyone makes 'little mistakes' from time to time - I certainly do but I really wouldn't appreciate it if someone told me (a family member for example) every time I misremembered something or repeated myself that I might be getting dementia and should be doing something about it.
I'm not sure there are answers to some of your questions. I don't think dementia always has a direct cause, though certainly some things make it more likely or make it worse. In mum's case, a fall and bump on the head (not serious though it later caused a chronic sub-dural haematoma) caused huge changes and took her from living independently and being generally OK, to needing 24/7 care.
The biggest risk factor for getting dementia is being very old. Like all our other organs, the brain ages and doesn't work as well as it used to. Same with hearts, bones, muscles. Some things we can treat - a hip replacement for example. But we can't fix brains. (Yet.)
If children got dementia you can bet we would have a cure by now. But it happens (mostly) to old people and - call me an old cynic but I don't think the pharmaceutical companies are very interested in keeping old people with dementia alive for a few extra years. Being extra cynical today, I'd add that the entire population aren't interested either because we do not value old people...
