If the blood is red coloured ..... likely he has had Hemorrhoids/Piles which have now started bleeding cause he might be constipated (passing hard stools with straining), this is usually a painless bleeding in stools...in the form of a splash of blood in the pot.
And if the blood is blackish in colour he might be having ulcers in the stomach...but would be a painfull in upper abdomen...specially with food intake.
Next Steps
increase water intake daily around 3-4litrs in 24hrs and Fiber intake should be 25gms daily for females & 35-38gms daily for males.
Health Tips
Consult a Surgeon for better Evaluation & Confirmation of Diagnosis n Proper Treatment.