Boiled hamburger mixed with cooked plain white rice is the usual thing for dogs with digestive issues. But if it's an appetite thing, he may like canned dog food.
First make sure his lost appetite is not because the meds aren't working. Has he been on them long? If it's more than a day or two, and he's not feeling better yet, I'd call your vet.
The pedialite is a good thing though. You don't want him dehydrated. You test a dog for dehydration exactly like you test a scouring baby calf.
Always drive the truck so you don't have to get out and open the gate.