we are programmed to believe that milk is the best food for baby for esp calcium or that it easily gets digested. but did u know that the number 1 allergy causing product is milk. just on milk allergies there are encyclopedias written. more than u as parents understanding your child, your child's body understands his needs. each cell in his body is programmed to help him grow stronger day by day. so if he's rejected milk repeatedly to the point of vomiting, is it really logical to feed him that which could be causing him problems. children associate good with emotions... if they see u r stressed out feeding them, they easily catch that and get stressed. ur child is old enough for semi solids and solids. he wants to explore different tastes. so give him the tastes. don't fret about how his bones will form and all that...if given the right foods rich in all the nutrients he will grow stronger even without milk. I have 2sons, 18 and 21 years old. both stopped milk at 6 months. thanks to God they r fine. I had to stop milk bcoz they develop early stage asthma due to it. immediately after consuming milk they would get a wheezy cough constantly till I nebulized them. hence they themselves gave it up. so don't make eating a war. make it a joy. give him whatever he wants to eat. and don't feed him at night if he doesn't want to. follow doctors advice. if he says ur kid is normal and growing well, no worries....don't compare or complain seeing other kids
I guess your main concern will be whether your child is getting enough calcium. If he is taking solids, you can try giving him food like cheese, yogurt, kales, broccoli, salmon, calcium fortified cereal, prunes etc which are other sources of calcium. You can also refer to this article for more information on the calcium needs, as well as a full list of alternative sources of calcium (if this is indeed your concern): http://homemade-baby-food-recipes.com/calcium-sources-for-your-baby/
Like the above say, my friend kid is like urs too, hence she have to use syringe to feed her milk and tell her firmly to swallow it. Intro more food which is high in calcium for them. Can give some basic supplements for him too. I think he will need pedisure, as there is most of the nutrients he need, although it's a bit sweet.