He may have a stricture. I have one and fissures as well from it and experience all of his symptoms. The pouchoscopy will pinpoint it for certain if he has one. i understand his pain. It’s understandably very hard to watch.
If he has a stricture they will dilate it. Some people have luck with this. I’ve had several and now am going in for pouch advancement as mine is very tight and has been giving me many issues, the fissures being the most painful. Please update us as to how he is doing. I’m sorry you are going through this at this time.