She was claiming to be lactose intolerant/has ibs but she eats junk foods that as someone who’s been diagnosed with both those disorders would make me violently ill. Doctors have told her to take meds but she refuses. I recommended lactase enzymes after she said she was lactose intolerant and she says they don’t work.
Depending on what illnesses you have you might be able to throw in some vague legal threats about violating the ADA because it sounds like by living with her you’re being denied your accommodations. Violating the ADA messes with any federal funding the school gets some they’ll be more responsive if they think their funding is at risk.