If a 2 month old baby sleeps through the night how much should he eat during the day?

Whatever he wants: Normal, healthy, growing babies eat whatever amount they want to eat, night or day. Avoid feeding during the night, after age 3 months. If he stops eating at night before then, don't wake him up at night. Avoid counting how much is eaten. In nature, babies breastfeed, so the amount they eat is unknown, and not looked at. We calculate the amount eaten ONLY if a baby is sick or not growing right.