This is really sad and sounds like elder abuse if she is not getting the medical attention she needs and she is being blamed for her failing memory and anxiety. She should not be driving at this point, and there are options to have caregivers in the home who are trained to deal with patients like her and can keep her at home where she wants to be until she is ready to go to hospice. If you and your sister is all she has, then you both need to figure out how to care for her.