Hello there. I can understand your concern. How much do you think he should be for his age? How tall do you want him to be at this age? He is normal, don't need to be too worried about it. He will grow as determined by his genetic make up. Give him a high protein diet, lots of greens, fruits and vegetables. Ask him to eat frequently. One glass of milk daily before bed to which nothing should be added. Best regards. Dr. Anil Kumar Jain.