Thinking of your family. Hope your sister is improving!
I was on life support for 7 days in a medically induced coma. I was in the ICU for 9 days and in the hospital a total of 19 days. I was the same as your sister, smaller size with anemia and had trouble conceiving my son. I had failure to my liver, kidneys and heart as well as ARDS, pulmonary edema, fluid overload. I received over 55 units of blood products and was also on dialysis.
The best thing you can do is be her advocate. Every morning I was told that my husband was part of the morning rounds with the specialists on my case. He would look over all the labs with them and ask what they are looking at today to get an idea where my body was. We were told that the kidneys are normally the first to shut down and the last to return. If you feel that you are not getting answers or any concerns addressed, ask for a second opinion or ask for the social worker to help. Become close with the nurses is the best thing I did - after I was awake I was very confused and they would sit with me after my family left and go over where I was and what they were thinking about doing.
We are all here to support you as you need us!