Herceptine

My sister was diagnosed with stage 3 breast cancer back in August of 03. She did the chemo and radiation. About three weeks ago they found the cancer had spread to her liver. They put her on herceptine. I saw here this past weekend and I don't see how she can survive. She has lost a lot of weight and her liver has swollen to the point that she pregnant. The doctors say the hercpetin needs 4 - 8 weeks to do its stuff. Has anyone experienced someone who looked like they couldn't possibly recover yet turn around? I love her dearly and it breaks my heart to see her going through this. I would appreciate any information you can provide.