I'm so sorry to hear about your sister's continuing fight. Metastatic cancer is cancer that has spread to other organs in the body. Breast cancer has favorite places to go. Usually to the bones, lungs, liver, and sometimes to the brain. We have women here at HealingWell who have lived for years with metastatic disease, so that is the good news. Some oncologists like to think of it as a chronic disease, like diabetes. While you may eventually die from it, if managed properly, you can live with it for a very long time.
I wish your sister well in her continuing battle, and you in your efforts to be a supportive, loving sister who is there for her no matter what. Believe with all your heart in her strength and ability to survive. That is the best thing you can do for her!
"There's a difference between a philosophy and a bumper sticker." --Charles Schulz