I don't want to get my hopes up, but he has seemed to improve since last night. After I noticed his color change, I checked on him periodically. He tried to get in his water dish a few times. It was a little sloppy, not as smooth as he usually does, but that is the first time since his illness began. While in the water dish, he shed some skin that was really dark gray. He didn't eat it, but it has seemed to make him feel better. His yellow markings are more yellow brown now, and he's way more alert. During the entire illness, he has been very compliant. I could do anything to him: pick him up, feed him, and he even tolerated being in his travel container to go to the vet. This morning he was very alert and when I put the saline solution on him, he tried to escape! I don't want to get my hopes up but those seem like improvements, right?