This is yet another reason why we need proper "aging in place" infrastructure like small retirement communities right near where people live, so people can both stay in their community but also get more appropriate accommodations as they age. Not only that, but those retirement communities will free up plenty of housing for younger people who are struggling to find housing.
I cannot fathom how an old couple manages to maintain a 5 bedroom, 3 storey house for just the 2 of them. Maybe a handful of times a year the house is full with family. It just seems like a lot of air to heat/cool, a lot of furniture that doesn't get used, a lot of appliances and land to maintain, and a lot of wasted room in the house when they probably only use a kitchen, bedroom, and living room the majority of the time.