The vet maybe able to see what exactly it is on x-ray or whatever they use and be able to tell you if it will pass on its own..if not i am sure even they can do something to help. Its better that then him to suffer if it can't pass. I hope for the best. I would hate him to suffer if its unpassable and they cannot do anything due to the size and such. That would be a very painful death. Its best to know one way or another anyways.