So glad to hear he is better!
I had a cat for years that had to be on a special diet for vomiting and serious thyroid issues. The surgery at the time was over 1k and I couldn't have it done, but found a vet who offered a more holistic approach.
We found some good additives to put in her food, which was a special food by Science Diet, and it gave her many extra years.
You know how I am about diet/nutrition... so if I ever get another cat (munchkin is allergic to cats right now) I'll leave no stone unturned in my food/best diet for kitty research.
(Maybe you should consider switching your major to Research and Development.
You've certainly had enough practice lately...