Common causes of bright red blood in stools include hemorrhoids and anal fissures. Need to know more details, e.g. complaints of pain or constipation before arriving at a provisional diagnosis.
Even though he has a family history of colon cancer, it is unlikely to develop at such a young age. Need to rule out pathologies of anal canal before going that route.
Next Steps
Consult a General Surgeon for proper examination.
Health Tips
1. Consume a high-fiber diet.
2. Avoid straining during bowel movements.