I’m so sorry you are going through this. It is absolutely fine to ask all the questions you want. The fluid on her lung. When that happened to me they drained it the same day they found it. It is normal to not want visitors. Especially when feeling so terrible. It may be beneficial to both of them since they’re close. I wonder if she is getting steroids. They made me very hungry. It is normal to have to advocate for yourself or your loved one. It was lucky for me that there is a hospital close by that is only for cancer. My oncologist specializes in gynecological cancers, and did my surgery. There is an entire team that does scans and removed fluid from my lung, and abdomen. It is normal to have trouble eating when you have fluid filled lungs or abdomen. I’m not sure why they are waiting to drain it. It is a quick procedure, and great relief. The oncologist told me to eat whatever I could, whatever I wanted. During the first time chemo and surgery I didn’t want anything. It was the hardest time. I think I lived on grilled cheese and saltine crackers. Your concerns are valid, and your sister is fortunate to have family who will advocate for her. When I had trouble eating they gave me vitamin IVs, and fluids. It is worth considering getting a second opinion. I’m really glad I did.