My sister obtained a POA for my father. My father had already been diagnosed with Alzheimer's/ Dementia when my father signed the POA. He was recently hospitalized in is currrently in ICU. My father never wanted to be kept on life support (artificial life) if something were to happen to him, but my sister does not seem to be concerned about his wishes. She never cares for my parents, I am their primary caregiver. I spend time with them everyday and care for them, my sister never visits but is quick to try and control every situation, even if it means to go against their will. Is there anything I can do to remove her as POA?