My friend has horrible hygiene!?

Okay my best friend has the worst hygiene ever! She doesn't brush her teeth, they're yellow and her breath smells DISGUSTING, like if she breaths to close to me I'll get nauseous! She also doesn't shave her armpits and they are insanely hairy, and same with her legs, it's a little caveman-ish actually. She's 13 and honestly I think it's really gross but she's SO sensitive that I just can't bring myself to tell her! I've offered her gum and stuff but she refuses! It's almost like she doesn't care... help me!