Hi if this bleed is not associated with pain than is generally due to piles and quantity of blood should be more. If this is associated with pain and quantity is less than this is due to fissure. At times there may be sigmoid colitis which leads to crampy  lower abdominal pain and may cause passage of blood in stool. You should avoid constipation, as this is the cause for piles/ Fissure. it's better to get evaluated , a short scopy done to rule out the underline problem. Give plenty of water. Get him evaluated soon. Take care.