> How many times have we heard parents say, “Oh, they’ll make new friends,” as if the relationships of children are so shallow and contextual that they can be swapped out like last year’s lunchbox?

This is where the author loses me; for several reasons

1) Parents might have several reasons for severing a child's friendship, whether relocating for a job, disagreements in the adult relationship, or disagreements in moores and values.

2) People will experience loss in many types of relationships. It doesn't mean they were worthless, in many ways this grief means just the opposite. It's similar important for people to be able to create new friendships with new people.