Tomorrow is my youngest brother’s last day of high school.

I still have one more sibling plowing her way through school, one last chance to impart advice that will probably be ignored, but I have, what I like to think is, a special relationship with my youngest brother. I’ve watched him go from a boy full of worries and doubts, who’d wander down to my house and sit on the back porch with me in stony silence, to an almost-man with plans and pride, eager to talk about them.

He’s not leaving for...