poor you and Panther...all I can think of is to get a second opinion...ask around and see if there is someone that everyone likes...

You could try a homeopathic vet.

And Craftlady seems to be having a lot of luck with Reiki. Maybe her Reiki person could recommend someone near you.

A radical thought...taking him off EVERYTHING and letting his tummy rest. And doing baby food for a day or so.

I am so sorry - I wish I had an answer for you.

HUGS