Your kid just spent two minutes in the box while the other team scored on the power play. The game ended badly. Now you are in the car.
What they are probably feeling: embarrassment, frustration, some guilt about the power play goal. They have already been in their own head about it for the last two periods.
What helps: “Rough one. You okay?” Then wait. Let them talk if they want to.
What does not help: any version of explaining what the penalty was, why it was wrong, what it cost the team, or what they should have done instead. The coach already covered it or will cover it. Your job is not to be the third voice in that loop.
If they bring up the call themselves and think it was wrong, you can agree or disagree simply. “Yeah that was close” or “Yeah, that one hurt” without turning it into a film session.
The rule: the drive home is not practice. Save any technical conversation for when the kid brings it up at the dinner table two days later, when the emotional charge is gone.
One thing worth saying at some point, not in the car but soon: taking a penalty at eleven and twelve is normal. The best players in the game take penalties. Compete hard enough and sometimes you get caught. That is the game.