It sounds as if he's not doing well. He should be seen and xrays of the chest and abdomen should be done. There are lots of things that can happen to cause problems without detection until xrays. Also, if he's still on steroids, the rimadyl shouldn't be given. Often back pain can cause the symptoms you're seeing and sometimes that's seen on xray and sometimes it's not. There are back pain meds that can be helpful as well. Please have him examined again by a/your veterinarian. Please consider xrays. It sounds as if he's too
painfulPainful menstrual periods somewhere in the body to eat.
A good place to go in your area to get answers is Wisconsin Veterinary Referral Center, Waukesha WI 866-542-3241. Dr. Gwenn Schamberger is the excellent veterinary dentists there. (I doubt you would see her initially.)