It's not a good idea to be feeding your dog people food. Find a high quality kibble you like - Fromms seems to be popular here - and feed him that exclusively at least until he is well. the dog needs the balanced nutrition found in the kibble. Wet food is not good for the teeth and the stool produced is looser and smellier although the vet might have him on a prescription food that they're giving him wet to encourage his eating it. Royal Canine is one of the companies that makes prescription foods. Science Diet is the other. Petsmart carries them but you do need a prescription. We've used them occasionally for both dogs and cats when the vet recommended it to assist with healing.
Save the liverwurst, string cheese and peanut butter to hide pills in so they are an extra special treat and he'll eat it.
Oh and since you don't trust this vet, switch. This site has a Vet recommendation page and Florida shows a bunch of them all over the state. I'm in Tallahassee and there are several I trust for bullys.