Could it have possibly already been in the toilet before he used it? Is he having any sx like abdominal pain or cramps? I've heard of tape worms before but I didn't think they were that long. If there was some way he could have saved the worm and taken it to the doctor or hospital maybe they could test it to see what it is. I don't know....just thinking out loud. It would freak me out, too. Hope you get some answers soon.