My dd hated cow's milk when I first tried it with her. But I kept offering, whenever we had meals or snacks or while I was waiting to make supper etc. She's much better with it now - still not drinking tons, but it's a supplement to morning and night bf's (which is all I'm still doing). I make sure to give her yogurt a couple of times a day and some cheese to up her calcium. So far so good. As long as he's getting several servings of dairy a day, it doesn't HAVE to be milk. The other thing she could try is soy milk or even some type of formula or other supplement if she's worried - he might take to those better!
Oh, and I use the Nuby soft spout sippy cup - dd never took a bottle and this was the best thing that I tried!