Re: So many question!
He doesn't need cow's milk. If he is nursing several times a night and getting a bottle during the day you are fine. Even if he wasn't getting the bottle he'd be fine if he's still nursing regularly. You can also provide lots of calcium through foods. Dairy foods like cheese and yogurt, if he can tolerate them, and if not dark green leafy vegetables and beans have lots of calcium.
My daughter never would take cow's milk, she is 3 now and still very rarely consumes cow's milk. Occasionally she'll have some in cereal but usually she wants it dry. And she'd rather dip her cookies in water than milk, haha. But she does eat lots of dairy and has a well-rounded diet in general so it's not a concern.
“We are not put on earth for ourselves, but are placed here for each other. If you are there always for others, then in time of need, someone will be there for you.”