Babyfood is always a good backup but you have to watch the sodium content. As long as thats not too high and there no garlic or onion powder then it may get his appetite back. Just try and give the meds after he eats.... or if its feasible, which it alsways isn't, seperate giving them by an hour each. That way his empty belly is overloaded with drugs at one time. There's also a prescription diet called A/D(anorexia diet)by Hills you can get from your vet...its made for animals that aren't eating so its higher in calories. This you can get from your vet.
Let me know if you have any other questions
Good Luck &
Best Fishes