Toddlers aged 1-3 need about 500mg of calcium per day. If he is not drinking milk and eating other dairy there are lots of other ways to get calcium. Milk and dairy products are just the easiest! Sorry the chart is a bit wonky and hard to read, but the first number is the serving size (1 cup =250ml which is about 8oz) and the second number is the amount of calcium --
Milk, whole or low-fat 1 cup 300 mg calcium
Soy or Rice Milk 1 cup 300 mg
White beans 1/2 cup 113 mg
Instant Oatmeal 1 cup 100 mg
Broccoli, cooked 1/2 cup 35 mg
Broccoli, raw 1 cup 35 mg
Cheddar cheese 1.5 oz 300 mg
Yogurt, low-fat 8 oz 300 mg
Orange juice, calcium fortified 1 cup 350 mg
Orange, medium 1 40-50 mg
Sweet potatoes, mashed 1/2 cup 44 mg
source:vhttp://www.keepkidshealthy.com/nutrition/calcium_requirements.html
HTH!