My DD is 17 months and still has night feeds most nights. I think for her she has bad dreams or just gets unsettled and feeding helps her resettle. When she was the age of your little boy, she would have big feeds at night and I chose not to take action because in my opinion, she needed it. She hardly fed at all during the day (she ate solids but never sat still long enough for BM) so despite the child health nurses advice, I figured i'd rather her just have it. The frequency dropped though when I started taking her into a quiet, dim room to drink during the day so she actually had a proper feed rather than hopping on and off repeatedly!