I am so sorry that your little Gabe is ill. I had a very sick pup a couple of years ago who needed a special diet. None of the commercial foods were really what he needed so my vet arranged a telephone/email consult with the vet nutritionist at Texas A&M. He reviewed all of my pup's vet records and made up a home cooked diet for him. The cost was $150 for the entire thing! I received two recipes...and he was wonderful about answering any questions that I had. Here is a link to information about him:
John E Bauer
I will keep your Gabe, and you in my thoughts and prayers.