His weight and height are both below the 5th percentile for his age. The recommendations with tube-feeding children are to tube feed at night, if possible. In your case have the amount cover his nutritional needs for the night feed so if he does not eat well during the day, he will get what he needs at from the night tube feed. During the day try to feed him regular food so he develops an appetite for food (will not be full from the tube feed formula). You can try to set up feeding him 3 meals of food so he starts to become hungry between meals and hopefully will not resist being feed orally. For the day time feeds suggest giving him a nutrient dense drink such as Pediasure or milkshake (milk and ice cream blended) in place of milk at all meals for additional calories and protein for growth and weight gain. Hoped this helped you.