I’m so sorry. Such a difficult situation. This sounds so horrid. It’s impossible to know what her wishes are. Refusing food but also ‘you are trying to get rid of me’ implies she doesn’t want to die? Somehow her mental state is thinking food is poison? Ensure will harm her? Because she doesn’t have the mental capacity to understand the consequences of not eating, or to communicate if she wishes to live or enter palliative stage, you’re in an impossible situation. Agree with Melba that checking what the legalities are for medical treatment for someone mentally incapacitated is important. Maybe also having a discussion with others who are close to her, and her doctors, what decisions would be the best quality of life for her?