Just to put an ending to this story, the little guy passed on yesterday. I kind of knew yesterday morning that he had had enough, and I had planned on calling the vet and bringing him in that evening, but he didn't make it that long. On a kind of happy note, I got to say goodbye to him when I had stopped at home in the morning, rushing to get to the hospital where my sister-in-law was in labor. I kissed him on the ear when I went back to work at 2, and my mother said that by 3, he was gone. So I really do believe he waited. I am so happy he isn't struggling anymore. Thank you everyone for helping.