He doesn't need to drink milk - if he gets calcium from other sources don't worry about it. Breastmilk isn't really about calcium, it's about all the other stuff in there, if that makes sense, so it's not necessary to replace it with other milk necessarily at this age, so long as he's eating a balanced diet.

Yep, that.
Totally unnecessary for him to drink cows milk at all. Follow his cues - if he doesn't like it, don't give it to him. (I hate cows milk i na cup.... will drink it on cereal or eat yoghurt, but drinking a glass of milk makes me want to vomit).
You could try rice milk, oat milk, soy milk or goat's milk... So long as he is eating enough food, there is no reason why he needs milk at all.