My 13month old has never taken a bottle or a paciffer. I am still nursing him and I am going to try to nurse?

him for as long as he likes (not more than 2 though). My question is...does he need to drink whole milk if he is nursing? He has cheese and yoghurt almost everyday and does take vitamins. He drinks water from a gl (doesnt take a sippy) but not more than two or three sips at a time. Do I need to try and get him to drink whole milk or is it ok for him to be without it?