Staging

My mother in law was diagnosed with ovarian cancer 1 month ago she underwent her 1st chemo treatment (cisplatin) last Thurs.Her abdomen fills up with acites (ascites) & must be drained every 3-4 days. Yesterday she was weak & confused she could not speak so I called 911 she was admitted to our Cancer Clinic. Her BP is 40 over 60, she is very short of breath she has an oxygen mask on but does not seem to make her breathe any easier. The doctors have not been very clear on the cause or how to rectify this problem. They have booked her fo r a full hysterectomy after her 3rd chem treatment. She is pale & the family is scared when they see her. I am trying to support the family the best I can but I feel I need the facts on what we can expect. I understand that staging can only be done during surgery but I feel that with her low BP & also lessened kidney functions her ovarian cancer is further along in the stages than we know. What can I do to better educate myself for the family. The kids are 16, 17, & 20 & as I said earlier they are scared. I believe that they are scared because right now there are no answers to any questions.
I appreciate any help.
Thanks in advance,
Debbie