My 90-year-old mother has a UTI and is refusing treatment because she has a living will. What can I expect?

She has been on a low dose antibiotic for years to keep the infections from occurring, but she still gets them periodically, especially since entering a nursing home two years ago. Her recent erratic behavior in the past few days indicated another infection, and when tested, her urine showed that she did have one, but due to allergies and resistance there is no pill form of antibiotic that she can be given. She is refusing to take any of her other medication - for high blood pressure and depression/anxiety also, and the nursing home has tried to set up an IV, but she refuses based on her living will. She does not want treatment, she wants to die and has expressed that wish for several years, long before this current infection set in. The nursing home has told me that the infection can cause sepsis which can cause death. I am just looking for advice on what to expect, assuming that she continues to refuse any treatment or medication.