The liver transplant isn't an option because the cancer has already moved.
The problem is where it has already potentially "seeded" but growth is not yet visible. Hence if it's already appeared on the liver, it's likely seeded in other places that CT scans etc can't yet see.
I'm going through this right now with my mom, for the 2nd time. The best hope/advise I could offer would be to explore your father's eligibility in clinical trials. Ixabepilone (approved in OCT 07 for metasstic breast cancer), in combination with Erbitux. We were in a stage 2 trial of these drugs until my mother developed an abcess on her liver and missed too many weeks to continue.
When we started the trial, her CA 19-9 was in the 19,000 range; when we stopped it was down to 2,482. A 90% drop, which is commonly unheard of. The jist of the combination of these 2 drugs was that it prevented the "seeding" and "growth".. something some of the other current drugs doesn't do.
We are currently using Gemcitabine & Tarceva; but the results aren't anything close to what we got with Ixabepilone & Erbitux. The doctors will tell you you can't judge the cancer just on the CA 19-9 level, which is true... but you also shouldn't ignore it if the number continues to increase. It means something is seeding/growing, they may just not be able to see it yet.
I'm desperately trying to get my mother's insurance to approve us switching back to the drugs in the trial. I feel like I'm in a race against an unrelenting clock.