There are so many places to get calcium besides milk, the issue is that babies can't eat as much of the greens, which is one place I get my calcium. well cooked and mashed Beans like chickpeas are soft and full of calcium. Fortified orange juice and soymilk are good. I found this website.
http://www.vrg.org/nutrition/pregnancy.htm (basic needs for infants) There are a lot of books out there. If you tell your doctor alternative sources I'm sure he will be reassured.