I just wanted to let you know I fought back from liver cancer which had spread from my primary stomach Cancer, I was expected to live 8 months at best when I was diagnosed. That was in the spring of 2001, my last scan in April show's I am still cancer free. I do not proffess to have near the knowledge of some of the other people who post such helpful answers on this forum but I can tell you what worked for me was a tea called Pau d'arco which comes from the inner lining of a South American tree. I also juiced and still do which is a wonderful way to get concentrated nutrition when you can't eat much. There is lots of info re the tea at the two websites I will post below.
Never give up...especialy if the doctors tell you there is no hope...prove them wrong!!
My greatest wish for your fathers full recovery,