What do they mean with 'dying from dementia'? As typically you don't die from dementia but something like pneumonia or something else. Personally, I wouldn't wish dementia on anyone and definitely wouldn't want to extend my life while having dementia.
You do if you're flying, taking Amtrak, or driving. Otherwise, no.
The issue here isn't about needing ID (that's not new), it's about a new requirement for an enhanced ID, called "Real ID", in order to fly. Your regular old ID doesn't cut it anymore.
This is actually a softening of the requirement. Originally, they were saying that you simply couldn't fly after the cutoff date unless you had a Real ID or passport. But so many people haven't been willing to get a Real ID that they had to back off just a little.