Interesting but not sure there is a clear benefit of knowing ahead of time when there's no treatment available. Knowing how you will end will significantly affect your outlook on life.
The only other options are (a) knowing after it's too late to do anything, or (b) knowing at the exact moment science makes a discovery. Since we can't know (b) ahead of time, we're left with either knowing ahead of time, or too late.
Knowing sucks, but it sucks less than any other option.
I subscribe to your opinion, however.
Eventually, she had to be moved to a nursing center where the health care costs are astronomical.
Of course no one wants to hear this news early, but in terms of preparations that can be made by family members, the earlier the knowledge the better.
When a family member is struck with an illness it does not just affect the individual, but rather the whole family.