I am very sorry to hear this news about your sister. I was there with my dad when things progressed and I can feel the pain that you are going through right now. I agree with what Lainy says about hospice and they will be best placed to deal with your sisters needs. My dad went through hospice care and I have nothing but great things to say about the care that he received from them.
Pain and other symptoms that can arise will be able to be controlled best with the hospice team and I know that they will be of great help and support to you as well. You know that we are all here for you as well always and will do what we can for you. I know that this is a frightening time and that you are scared, so please come here as much as you want. We are here for you.
Any advice or comments I give are based on personal experiences and knowledge and are my opinions only, they are not to be substituted for professional medical advice. Please seek professional advice from a qualified doctor or medical professional.