Blood in the stool can be from a number of causes. Most common particularly in a relatively young person is a ruptured hemorroid due to constipation. This typically is seen as bright red blood. Bleeding from anywhere in the GI tract except the colon will almost never be bright red, it will appear as dark tarry looking stools. Other causes of bright red blood in the stool are inflammatory bowel disease such as ulcerative colitis and/or crohns disease. These are usually accompanied by crampy abdominal pain and diarrhea, but not always. In older individuals you have to consider the possibility of colon cancer. If your friend was a patient of mine, then I would want to get a colonoscopy done to be certain. Hope this helps.