[UPDATE]:
Thanks everyone for their kind words. I came home from an appointment just now and found him collapsed on the floor. We will be saying goodbye tonight.
And thanks to Murphy Road Animal Hospital for dispatching a doctor to our house to handle this. I just couldn't do it at the doctor's office, he was so frightened there.
Today has been rough, tomorrow will probably be worse. One of our dogs is losing his battle with cancer rather quickly, and will need to be put down. He has a tumor on his liver and he's now unable to hold his urine, eat, or sit still for more than 5 minutes. The vet has given us a tranquilizer to calm him down and he will be put down tomorrow.
Boomer wasn't the brightest dog in the world but he was the sweetest. He's always had a big heart -- figuratively speaking, though an irregular heartbeat was one of his many medical ailments. He's also suffering from dementia, and over the past few weeks has steadily declined. He now gets lost in his own yard.
Farewell to a sweet dog. Farewell, Boomer.