Do people have an obligation to their parents in their old age?

Obligation - No,not at all
Love - 100%. How can not people love their elders?

The Bible teaches us to honor thy mother and father

I hope that mine will not let me down

A moral obligation.

Probably

Biologically No.. Parents owe everything to their children. Emotionally.. Thats a case by case. We looked after both Mothers after their husbands passed, because we felt it was right. And they both had not family in this country.😷

Nope.
Parents owe their children, not the other way around.

I don't know about an obligation, but I'd hope there was enough love to make people care about their parents.

No child has an obligation to their parents, every parent has an obligation to their child until they are adults.

Hopefully if both behave reasonably they can be friends much longer.