I am so sorry for what you're going through. I lost my father at the same age, and it's hard. There's 5 of us, too, and the age ranges are strikingly similar. Again, I know it's hard.
The problem is that cancer is aggressive, and when it's spread to the stage IV category, any organ that they transplant will just get the cancer right back, maybe not immediately, but it will. Stage IV disease means the disease is nearly everywhere, in almost any body tissue available, and it just isn't feasible to make a sick man go through a liver transplant, which is horribly rough on the system, just to get cancer back in the organ. It's just not an option.
Having said that, my father was diagnosed with stage IV cancer. He had no clue that he was sick, and I'm sure your father is the same way. Given that, my father lived for 2-1/2 years, and this was several years ago. Advancements in the medical community continue to grow exponentially. Do yourself and your family a favor - get to the nearest teaching hospital and find aggressive physicians to treat the aggressive disease.
My best to you. I've been listening to cancer doctors speak for years now, and I'm a nurse, so I can say that your dad's doctor is right. I hate it, but he is. It's not right to play merry-go-round with organ donation, especially when he needs to get started on chemo right away to give him a chance for better long-term survival. It's not just in the liver. It's probably in the bone marrow and the pancreas can't be replaced, and that's where the cancer originated.
I'll keep you in my thoughts. Feel free to contact me if you have any other questions.