I'm not sure what the problem really is here?
He didn't coddle her. My daughter is on a swim team and if she shows up for practice and says she is tired she is likely to get the same response.
If she shows up at home and says she is tired I am likely to ask why and mention that going to bed earlier might help.
Maybe it was said in a way that was "more harsh" than necessary but when he realized he apologized immediately which is more than a lot of people would do.
I assume she didn't say to the teacher I just got my period and it is new for me so there are extenuating circumstances.
It seems to me that you might have an issue with the fact that the guy is in NA and are looking for an excuse to pull her from lessons.
If you don't want her around this person just end the lessons. You don't need to justify your actions to anybody.
I occasionally used babysitters that I never had back "just because" and that is a good enough reason for me as a mom. Don't look for reasons that aren't there.
JMHO