The soaking recommendation may also help. The rationale on that is you need to replace the fluid loss b4 you replace the solids. Feeding a dehydrated animal is not the route to take to bring the bp up to regular feedings. Actually the soaking worked in my case just for the record. I know you said you've seen him drinking but we all know bp's really don't drink water that much. They do absorb fluids through the cloaca and actually the cloaca is like a mini sponge hence this is why your vet recommended the soaking. Hydrating him will go a long way. Next, ditch the carpet. It looks nice but you should switch to 100% cypress mulch to help him get back to feeding. There is a great article by The East Coast Reptile Breeders titled " The Enigmatic Ball Python Appetite" by Colin Weaver. He talks there about the benefits of 100% cypress mulch on non feeding ball pythons. Immediately go and check out his article! Good luck. Hope this helps!