Who will help in your old age?

Buying plants at the nursery the other day, I noticed the supply was dwindling and asked the young owner if she was preparing to close for winter. It turns out she’s preparing to close forever. Her father-in-law has Alzheimer’s and she and her husband are moving to Corvallis (about 60 miles away) to help him and his wife. “They need us closer,” she said. She seemed to have no doubt about the right thing to do.
When I ask childless women whether they worry about who will take care of them in their old age, most reply that people can’t count on their kids to be there anyway. Do you think that’s true?
Let me turn this around a bit. Would you uproot your life if your parents needed you? Have you done so or known others who have? Why or why not?
I know what I’d do, but I’d love to hear your answers first.
Sue