OOTT... I have been in cat rescue for years, mainly that's what I do besides work. I am the vet liason and make medical decisions for the cats. I have seen every conceivable illness and injury. Hundreds of cats. Not kidding . YOU CANNOT DRINK, you will regret it
Do not assume ANYTHING, take him to the vet ASAP. He needs Xrays at minimum. If nothing there then bloodwork. Go!