In response to an ask you answered earlier, imagine the teachers reactions the first time they saw All Might cough up blood.
OH that’s a interesting thought!!
It would probably be surprising, to say the least. It sort of depends on the situation, though. If Toshinori has a coughing fit and his hand comes away spattered with red that’s a little more calm than him keeling over with blood dribbling from his mouth.
Mic might be lowkey freaking out and trying to help, Midnight would be worried but respectful of Toshinori’s boundaries, and Aizawa would try to give him the space he needs.
If it becomes clear that Toshinori needs help (choking on the blood in his throat, struggling to breathe, etc.) then they would act accordingly. They’re all professional heroes, and know how to give basic first-aid and help injured people. Midnight might sit next to him and try to help him with her quirk, and Mic would tell stories. Aizawa wouldn’t say anything, but he would hand over tissues and something warm for Toshinori to use to soothe his throat.
If he’s in a really bad spot, Toshinori is light enough and they’re all strong enough to just help support/carry him to Recovery Girl.
While it might freak them out a little bit at first, they’d get used to it and help where they could.