Blood in stool.... if it is bright red blood, then it is probably not from something that he ate. If he had a bleeding ulcer that was bothered by ibuprofen etc, then the blood would be partially digested by the time it hit the toilet. You would see tarry stools, or coffe-grounds type stools. If it is bright red blood, it is from a source much lower in the intestines, probably from internal or external hemorrhoids.
Unless it is a large amount of bright blood, in which case it could be an active bleed... and an emergency.
Just a sidenote... colon cancer is one of the only completely avoidable cancers. colon polyps, (which can cause bleeding) that are caught early can simply be removed without further issue. If left, they are the precursors to colon cancer. I am a firm believer in natrual medicine, but I also used to be an oncology (cancer) nurse. I would hate to see you ignore a condition that could easily be taken care of at this point, but be a train wreck if left unchecked.
For me, and my naturopath agrees, I go see a medical doctor, get all the medical tests to rule out the major surgical issues, and then when they simply label my problems "IBS" and send me out the door with prescriptions, I toss the prescrition papers and head to the naturopaths office for some health intervention.