Frequent hunger can be due causes like diabetes, hyperthyroidism, and other systematic diseases etc. Or it can be due to reflex action to Relieve gerd SYMPTOMS which have become a habit. Treatment is ACCORDING to the cause.

Firstly like to rule out any organic cause by checking his blood tests and ugi endoscopy even if previous one had shown only GERD..there are fifferent grades and associations of the same. If everything turns to be normal then probably need to space up his meals with small frequent meals so as to get sense of full ness in stomach without increasing quantity of food.