I am a nanny to a 4month old ,who isdisplaying all the signs for needing extra food. He is already having 240mls at each feed(4 feeds ,plus a 100ml top up) and is draining the bottles. He is very unsettled and is waking at night haveing been sleeping through for at least the last month. He weighs over 18lbs and is on the hungry milk . How do we give him more milk?