And with your waste pocket wrapped around your waist, you attended dance practice only to hear from the other members that your waste smelled. "
iirc this was not what his father said. The letter mentioned members noticing weird smell and not knowing what it was about, and not them going to Kyuhyun telling him he smells.
I also read that Boa was mad about something else involving a dancer(?), but I don't remember details and am not really sure.