“The other boys, all non-Jewish in the vehicle, strongly objected and made him turn it off.”
Sounds like the kids took care of it.
Kid should be shunned and ostracized by the other kids as in “get out of here, loser freak.”
The kids took care of it - that one time. I would talk to the dad/ ‘I thought you’d like to know. I certainly would if it were my kid.” And then document.