You were eating lunch with your son. He seems to be finished eating. You want to ask if he's finished so you can clean up.
This question means "Are you finished?" It sounds very gentle, so you can use it in situations like when you're:
- seeing if your young child is finished eating
- a waiter serving customers at a restaurant
- clearing out dishes for guests at a dinner party that you're hosting
"All ___" often means "completely ___". That's what it means in this case.