If my elbow is broken, I can't cook efficiently. If it doesn't work correctly, same. If walking to the toilet saps my energy, I shouldn't be expected to do the same.
I should also now mention that elderly doesn't mean you are sick. Loads of folks are busy throughout old age. "sick" doesn't always mean you can't do anything, either, and I'm pretty sure the Amish communities take care of folks that can't.