Sour, I'm sorry the news was so bleak. You're right, sometimes the only thing you can do is give them a few more comfortable days and then let them go. In the animal hospitals where I worked, we'd so often see dogs that were so sick they weren't living a life - a sweet little Norwich Terrier named Lucy comes immediately to mind. She was blind and deaf, and every other day she was brought in for life sustaining sub-q IV fluids. She'd just lay there on the table with the bag of fluids hooked up and running in not knowing what was going on around her. We've had dogs that paced their small enclosure in tight circles all day long, and in those enclosures we used Dri-Decking, which looks sort of like flattened Legos.....we'd have to bandage their feet when they came in or they'd leave with bloody paws from the constant pacing. I've had to coat the tongue of a Pekingese with oils because he could no longer pull his tongue into his mouth and it would dry out and crack open, and that same dog also required eye ointments because he didn't blink enough to keep them moist.
But they "loved" those dogs and couldn't imagine their lives without them, so the dogs (and sometimes cats, too) suffered just so the owners didn't have to make that final call. We could suggest it, but we couldn't do it without the owner's permission. One of the animal hospitals I worked at was also a big boarding kennel, and we did have one dog die while the owners were out of town. This poor fella had to have enzymes sprinkled on his food to pre-digest it, he was totally blind, he was 17 years old, and kidney stones were tearing him up. Yet the owners still came down on us hard, accusing of "euthanizing" Mr. Bancroft while they were gone because we'd "always been nagging them to kill the dog" so we must have done it while they were gone because he was "too hard to take proper care of." Yeah, right.