Hello, I'm Dr. Deb and will do my best to help you today.
I'm sorry for this concern about Pepper. In general, the presence of a small amount of blood denotes an irritated colon and nothing more serious than this. Internal parasites, dietary indiscretion, Inflammatory Bowel disease are just a few of the possible underlying causes.
If there's a profuse amount of blood, then that's a different story and could potentially be quite serious.
If Pepper's stools are loose, then a bland diet of boiled, boneless, skinless chicken breast and 20-minute white rice is often enough to return the stools to normal.
I also recommend a probiotic such as Forti Flora which is often available at local pet/grain stores or online.
I'll sometimes suggest Pepto Bismol as long as the patient isn't vomiting nor currently taking steroids or nsaid medication at a dose of 1 teaspoon per 10 pounds of body weight twice a day.
It might be prudent for your brother to have a stool sample checked if one hasn't been done recently but I would reassure him that the presence of a little blood in and of itself shouldn't be alarming.
I hope this helps. Deb