It certainly takes a special kind of person, being a self starter, someone who always find something to do, and more goes a long way. I watched my father's brother slowly deteriorate from Parkinson's. From losing the ability to ride a motorcycle to even driving.
It also affects people in so many different ways, in my uncle's case the later years walking required a conscious effort to stop moving if shuffling ensued. If you stopped him a moment he could start walking properly. Little things that just required a mental reset of certain muscles. A body that knew how to do the motion but occasionally needed a reset.
I really don't know if I faced such an issue if I would have the optimism but we can all hope
Can you imagine how much worse his last 30 years would have been without it?