Is This an Appropriate Question?

I think of this every time I do laundry.

I used to share a washer/dryer with my father until he passed away. During this time, I was walking past him in his favorite chair, and he asked me to sit down. Even as an adult, I began to worry that I was in trouble. This sounded serious. Finally, he asked me the question that had been burdening him. He said, "Do you wear underwear?"

Stunned, I said yes, and then he said that earlier that da,y he had taken my finished laundry out of the dryer and noticed that there wasn't any underwear among my clothes. It made him wonder.

What do you think? Was this a reasonable question, or was it wildly inappropriate, or somewhere in between?