Hey! Why not?
Some grandfathers have everything they need: a full-featured, available, caring network of spouse, kids, grandkids and pets to look after them and be looked after; some,unfortunately,don't.
And yes, grandmothers as well as grandfathers are included in this discussion(No sexism tolerated on this blog; although we walk on the grey line past the censors from Time to time).
Sure, the fact that they are grandparents means a network once existed; but it's no secret in this world of ours that these networks don't always function very well. Even grandparents--old but still human--get divorced; kids move to the other side of the country; grandchildren,if their grandparents are lucky, go with their parents. Dogs and cats are the next best thing to family, but they, like every carbon being, die. And all too often the old are forced by circumstances beyond their control to live where pets are unwelcome. So, family out of town? No pets allowed? It's time to think about getting a robot!