With bloody stool, there are so many things that could
be a problem. Your current Vet's diagnosis sounds a little suspect to me but
. If he were mine, I would be getting a second opinion with a complete physical exam, blood panels etc. In terms of $$ and time expended though, you should be aware that he will likely need an x-ray and ultrasound to check for an obstruction or physical abnormality. Keep us posted!