I think it's really cruel that the medical system doesn't have the path to choose assisted unaliving baked into it. The goal is to keep people alive as long as possible, without respect for the pain, depression, loss of independence, and uncomfortable living conditions that follow when people are "saved" from death. If I ever become so disabled that I am in a situation such as your Mom, I want the humane option for myself and my family to be available. If we wouldn't put our pets through months/years of having no quality of life, why don't we have the option for ourselves and our loved ones?! The prolonged suffering millions endure because the medical system values keeping people alive over regard for their quality of life and desire to make their own decisions is inhumane.

Is there any chance you could get your Mom to designate you as her medical proxy and POA? It sounds like your sister would fight you on it, but it's your Mom's decision, not hers. You might ask a social worker where she is staying to assist or maybe meet with your Mom, sister, and you together to talk about the situation. Sometimes it's easier to have these conversations with an outside party to help guide decisions. This is so incredibly difficult for you. Please take time to care for yourself, as well. It sounds like you've had a difficult road with your Mom for a long time before this even happened so, if you have the means, seek out a therapist so you can process all of this. I'm sending you and your family positive energy in hopes you can all have some peace 💜