The first time I heard my toddler curse another driver from the backseat, I realized that our kids learn an awful lot through observation. The key word being “awful.” Whether we’re driving aggressively, snacking unhealthily, or saying, “No, sorry,” to the panhandler outside the market, our progeny are watching. They’re listening. They’re learning. It’s unnerving.

We try to model thoughtful grown-up behavior. We try to embody — or at least convincingly imitate — the people we hope our children will eventually become: Respectful and responsible, courageous and considerate. We’re even careful not to gripe (out loud) when our own parents call during dinner, because someday that will be us. We’ll be the ones phoning our kids at inopportune times, and by god, they’d better answer with smiles on their faces.

But right now, we’re facing a tough grown-up task that’s made all the tougher under our kids’ searing scrutiny: managing our aging dog’s demise.

Jasper is 15, which is a-hundred-and-ancient in dog years. The boys have never lived a day without her.

Once the energy core of the family, she’s now a fluffy but matted rug that lies against the front door and can barely be budged when we come and go. She still barks, but it’s mostly at us, since her cloudy eyes can’t always tell who we are.

She’s stone deaf. Her hips slip. She sometimes leaves messes on the floor. And we invest more each month in her pain pills than we do in our boys’ college savings.

But this is not a woe-is-my-dog column. Anyone lucky enough to have had a pet evade cancer, coyotes, and car tires through four presidential terms must eventually grapple with the onerous decision of when to say “when.”

Here’s the thing, though: Grappling with it in front of your wide-eyed kids is extra-damn-awful.

All the normal end-of-days considerations are there, petty problems of convenience and obligation vs. ponderous notions of mortality, purpose, dignity, nature, pain, and other concepts that strain the thin skin of my intellect. And there’s an additional worry: What will our paltry coping strategy teach our kids about death? About life?

The decision about when to “put down” our pet can’t be made in a vacuum. It can’t be a quiet, guilt-tinged pact between me and my spouse. I may be more paranoid than the average parent, but I can’t shake the feeling that its repercussions may affect our own fates.

Someday — if we’re lucky — we’ll be old. Deaf and cloudy-eyed and reliant on expensive pills. Not sick, not broken, but, okay, fairly useless. What will our actions now teach our kids about coping with such infirmity? How do we dare claim to know when a loved one is “ready to go”?

I don’t know if children will ever have the legal right to decide whether to euthanize their parents. At this very moment — having just snapped at my kids for eating potato chips on the couch — I rather hope they don’t.

But if they do, then I hope what they learn from watching Jasper age and fail is the same thing I’m reluctantly learning: that life, and love, do bring pain. And that the best we can do is face it honestly.

This week, after completing his daily chore of feeding Jasper her mix of meds and kibble, our oldest came in with an empty prescription bottle.

“Jasper’s out of these pills,” he said. “You need to get more.”

My husband and I looked at each other.

“We’re not… ,” I started, feebly. “Sweetie, we’re not … going to get any more pills.”

“Oh,” he said. And there was a thick, aching pause before he finally spoke again. “Okay.”

I liked it better when he was swearing in the backseat.