How does Grandfather's reaction to Phoebe describing Nadia as American resolve the tension between her and her grandfather?

In the story Blue-Sky Home Grandfathers reaction shows that all he has been trying to do is to make Phoebe feel like a true Greek. She realises this when she sees Grandfathers reaction after telling him that Nadia is an American just like Phoebe even though her parents are originally from Pakistan. He seems to realise that no matter where you are from you can be beautiful and he sees that in his grand daughter Phoebe.