This girl smells what do I tell her?

I went on a school europe trip and there was a girl, lets call her M, who didn't shower all the trip -2 weeks- and didn't change her clothes -pants and i'm guessing same with not changing underwear-. Her breathe stunk of cr*p and she smelt of rotting trout. Her teeth had so much yellow... "gunk" on them it was disgusting. During the trip we had to stay over night on a train and in our small room we were stuck with her and the whole room stunk of rotting fish. I never even believed that vag. could smell like fish, but trust me IT DOES. I had the bunk above her which sucked. We had to keep the small window open and we were freezing and there wasn't many blankets to go around. Every student -around 45-50- complained to the teachers and soon they forced her to shower once, but i'm sure this isn't healthy for her. What do I tell her?