Hang in there. First of all, your mom may yet be diagnosed with something that's easier to treat. But if they do find ovarian cancer, no one can tell you where your mom fits in to the prognosis statistics.
My world imploded in June 2007 when my mom was diagnosed with stage 3C ovarian carcinosarcoma, a very rare and aggressive form of ovarian cancer. I cried for days. She came through the surgery very poorly and had heart and lung issues which made me assume that chemo would just about do her in. I was (thankfully) wrong. My mom is getting a super strong chemo program to deal with the sarcoma part of her cancer. And she is tolerating it exceptionally well. Nausea which is controlled with pills and exhaustion. She just finished her third course of chemo on Friday of last week (3 more to go.) Yesterday she went to an art show. And today she went on an excursion with friends to do photography.
My #1 advice for your mom (if she has ovarian cancer) and requires surgery is to go to a gynecologist oncologist. According to the statistics, they are better able to identify and remove as much cancerous material as possible. And my advice to you (which I remind myself of every day) is that until someone tells you otherwise, there is no reason that your mom can not be one of the survivors.
Hugs from Christiane in OR