Thanks & update
Thanks so much for "listening" and for your support. Lincoln slept hiding under the bed all night, which would have been unheard of before this. We felt he was detatching and would have gone off to die if he was an outdoor cat. Still no food or water (about 3 days now), and his breathing was becoming rapid. Vet confirmed this morning that we'd have to treat both the cancer and the liver dysfunction and that it would be a long tough go of it. Vet also confirmed we'd have about a year at best. He has always been a big, strong, proud boy, and we just couldn't bear to see him whither away. After much soul-searching we decided to have him euthanized this morning. We had a great morning with him and let him roll around outside as much as he wanted. He went to sleep in our arms and that was that. He'll always be our boy.