BACKSTORY: A family is such a laboratory for children in which to learn how to live among other humans. When the girls were very young, we made up a song for them called “Loving Sisters.” They always liked to sing it because it was about them and even had their names in it.

In their later childhood and through their teens, we interceded in their squabbles, not to arbitrate a resolution, but to caution them about the way they argued. Keith would take those opportunities to remind them there would be a time in their life when we were gone. He’d say it was important to remember their sister was one person they could always count on.

I still remember the time Maggie responded to their father’s umpteenth lecture by asking, “Is that true, Mollie? Can I count on you?”

Mollie: “Sure, Maggie.”

And then Maggie reached out and started poking Mollie as she counted, “One, Two, Three, Four …”

(Smart asses! But at least they stopped fighting).