Comment by mmooss

When a relative in the generation before me lost the last person in the generation before them, they surprised me by saying, 'I'm all alone now; it's just me'. There were no parents, aunts/uncles, etc. to advise them, support them, guide them. They faced the wilderness on their own.

Another way of looking at it is, when you switch roles with your parents, and you become their caregiver, their source of strength, their guide through the world. When they can no longer help you. One example is the Godfather, when Al Pacino's character starts caring for Marlon Brando's.

(Other commenters are taking this idea far too literally, looking for exceptions.)