My third grandchild was born on a Monday afternoon, just hours after his parents arrived at the hospital.

My third grandchild was born on a Monday afternoon, just hours after his parents arrived at the hospital.

My husband and I, by prearrangement, picked up our nearly 3-year-old grandson at day care on his brother's natal day and stayed with him at his house until the family was reunited.

The next morning, before we took the new big brother to visit mama, dada and baby, we fashioned a bouquet from a small jar and a couple of blossoms from the crabapple tree outside my daughter and son-in-law's back door. My grandson was holding this offering in both hands as the three of us walked through the lobby doors, comprising a no-doubt familiar scene for the several hospital volunteers standing at the information kiosk.

"Are you a big brother?" one of them asked knowingly.

My grandson paused in his march to the elevators. "I'm wearing two pairs of underpants," he said.

In fact, he was. In the excitement, I'd practically forgotten that he'd made this sartorial decision hours earlier.

"They might feel kind of bunchy in there," I'd mentioned when he pulled them on, but what 2-year-old makes decisions based on logic, or even personal comfort? Pick your battles, I reminded myself.

After flinging himself at his parents, the new big brother asked to hold the baby. He climbed onto the couch, allowed a pillow to be placed across his legs and waited as the tiny morsel in a pointy cap was laid on his lap.

This suddenly huge boy put one hand behind the baby's head. He bent down until his forehead touched the baby's and left it there for several silent seconds. The rest of us watched. I realized I was holding my breath.

Since that moment, preserved in my memory as if in amber, this boy has resumed his routine. He admires his rain boots, wants several thousand drinks from any water fountain and sings songs from-seriously-the musical Hamilton. His brother rarely comes up.

We know, of course, that his life revolves around his family of, now, four. We just don't hear about it. Because he feels no threat, no loss, no longing for what can never be again, he's free to focus on the minutiae of what's right in front of him.

He's continued to attend day care while his mother is on leave from her job. My daughter had hesitated to clarify this arrangement, lest he rise up in outrage, but all was revealed one night at the dinner table, when he asked his parents outright who was caring for the baby during the day.

"I'm staying home with the baby for now," his mother told him gently.

She braced for heartbreak-"While I'm kicked to the curb?"-but her boy merely nodded. Makes sense, the nod said.

His understanding that the baby needs his mother, but he needs to be in preschool. That moment of attunement with the brother he'll know longer than he knows his grandparents or even his parents. His preoccupation with his own underpants (plural) even as the tectonic plates of his life are permanently shifting.

My granddaughter is three weeks younger than her 2-year-old cousin. She, too, is a dazzling mix of intelligence, humor, curiosity, perception and noisy illogic. Her parents have said she can be delightful for hours, then within seconds make them consider leaving her on the curb with a "Free" sign.

The Longest Shortest Time is what Hillary Frank named the parenting podcast she founded and hosts. I can confirm the title is descriptive. So is Beautiful Chaos, but maybe that's just my more recent perspective.

Margo Bartlett and her husband have two daughters, two sons-in-law, three grandchildren and two car seats. She also writes the Just Thinking column for ThisWeek Community News. You can reach her at margo.bartlett@gmail.com.