Willy is doing remarkably well. On April 10th, the vet said he had a week or 2 to live.
Well, he's still going strong. He is eating more -- though he is still skinny. He's running and playing and enjoying his time outside in the pen soaking up the sun and chewing on grass. He sleeps a little more but he isn't isolating like he was before.

Brittany (the vet tech we hired to give him sub-q fluids when I'm away at work) thinks he's doing very well and suggested we take him back to the vet to get his numbers again. During the April visit, the numbers were so bad that the vet didn't think it was worth testing him any more.

I have no idea if his numbers have improved, but he is definitely doing better with the fluids every other day. I'm going to take him in to get the blood work again and see what's changed. We're told that his kidneys will eventually get so badly damaged that they won't be able to process the fluids, but for now he's giving us every sign that he is enjoying life. So, we'll keep up the "water and fish".