Found this fic once and it was really good and have been searching for probably a year. Here's what I remember:
One of the band kids ruins the sheet music falling down the stairs. Turns out he did it on purpose bc they band/set/costume people never get any appreciation. I think Blaine is teaching the ND, and it turns out this kid (I think his name is Felix) is Sebastian's younger brother and is being abused. He has an injured shoulder during this fic, and I think there's a scene with Felix and Blaine in the bathroom where Blaine asks him to take off his sweatshirt so he can see the damage and Felix says, "I don't have to" and Blaine replies, "you're right, you don't, but then I can't help you."
One of the band kids ruins the sheet music falling down the stairs. Turns out he did it on purpose bc they band/set/costume people never get any appreciation. I think Blaine is teaching the ND, and it turns out this kid (I think his name is Felix) is Sebastian's younger brother and is being abused. He has an injured shoulder during this fic, and I think there's a scene with Felix and Blaine in the bathroom where Blaine asks him to take off his sweatshirt so he can see the damage and Felix says, "I don't have to" and Blaine replies, "you're right, you don't, but then I can't help you."