Christa-
If he does continue to vomit, I would honestly have him rechecked for an obstruction. The vet couldn't detect Callie's on X-ray and it was only through ultrasound that something was seen. Did he eat anything solid at the vet clinic? Callie didn't vomit when she was given her anti-nausea medication every 8 hrs and I had to force feed her to get her to eat. We were at the vet clinic for an entire week straight before the surgery was done; she's doing so much better now but refuses to eat much of her solid food unless there is some soft on top. Good luck and let us know how he is feeling!