Speak less than thou knowest

Nugget and I are in the midst of a crazy month of travel to see various family. We got back from San Francisco yesterday and are heading to Chicago on Thursday. Apparently it's a good thing we are traveling so much; I discovered yesterday that my Nugget, now a small-town boy, is in need of a little broadening. We were on a crowded parking shuttle, going from the Seattle airport to the lot where we left our car. It was one of those mini-buses, with seats facing each other around the perimeter. Nugget sat on my lap in a corner seat. Directly in front of us sat twin boys, probably around 8 years old. Their mom was next to me, and their dad and grandma were toward the front. They were black.
Nugget quietly contemplated the little boys for a minute, then said, "Mom?"
I was looking up the ferry schedule on my phone. "Yes?"
"Why those boys have funny hair?"
I froze, afraid to take my eyes off my phone. I could feel everyone on the bus waiting for my answer. I think we were all dying inside, except everyone else got to think, "thank god that question wasn't for me."
"I don't think they have funny hair," I said finally, "I think they have very nice hair. Maybe they think your hair is funny. Do you think so?" Nugget laughed and shook his head.
For being on the spot, I think I didn't do too badly. But the conversation wasn't over.
"Mom?"
"Yes?"
"Why they have those things on their ears?"
Oh yes. The boys had hearing aids. Because my preschooler wasn't satisfied with stomping his way through one highly sensitive and charged area like a bull in a china shop. We got the twofer.
"Honey, it's not really polite to comment on what other people look like or are wearing." Not a very good answer, but I was done with this conversation. In retrospect, I probably should have just explained what a hearing aid is. Fortunately, the boys' mom came to my rescue.
"They don't mind explaining what those are," she said. She prompted her sons for an explanation, but they apparently minded.
"They're going to have to explain them at school tomorrow," the kids' dad said. Guess my tactless son and I had given the family a practice run for the first day at a new school. Yay us.
Mom gave up on the boys and explained the hearing aids to Nugget. I struggled to come up with a warm and jolly comment to put the whole discussion to bed, but after considering and rejecting inanities like "Isn't that nice!" I just turned to the mom and said, with obvious relief, "Thank you."