Slick, I'm so sorry to hear this. Is he a hard cat to pill? The reason I ask this is that maybe giving him some pepcid would help him. I don't know if your vet has ever suggested this or not. I'd start with 1/4 of a tablet in the morning and then 1/4 in the evening. This might help to settle his stomach and help him feel more comfortable. Lots of prayers and positive thoughts are being sent his way. Please take care. (((HUGS)))