My sister moved to our state in order to help my mom. She had diabetes and while she recognized it and mostly took care of it, she would use the diabetes to get her way. Any little emotional trauma and she would allow herself to go low blood sugar to the point of near coma. The same paramedics came out time and again, each time telling her she was damaging herself.
One night, she took it too far, went into a coma and died. She was 53. Do whatever you can to get your wife to recognize and treat her medical condition, but understand that you cannot make someone live differently.