I have been sensitive to lactose since birth too... around 18 years old I have learned to understand my body on which days are bad days and I should eat NO lactose or sometimes I have good days where I can have a glass of milk, cheese or ice cream. I limit my intake and the more I have latose the more it disagrees with me so limiting it is really key, the lactose pills never really worked well for me so limiting is sometimes the only option.
With that talk your child's pediatrician and tell them your concern they will be the best in telling you what you can do to get additional calcium. I take pills calcium and vitamin D, but they have to be spaced out because your body can only absorb a certain amount of calcium at one time. Also the amount I take will be different then someone else's amount. Also there are MANY other foods that have higher calcium in it then milk also many things are enriched with calcium now so chose those items too.
Non-Dairy Calcium Rich Foods
--Salmon
--Tofu
--Rhubarb
--Sardines
--Collard greens
--Spinach
--Turnip greens
--Okra
--White beans
--Baked beans
--Broccoli
--Peas
--Brussel sprouts
--Sesame seeds
--Bok choy
--Almonds
Calcium Enriched Foods (read the labels to see if they are calucim enriched)
--Calcium-fortified breakfast cereal, including General Mills Whole Grain Total, Total Raisin Bran, Total Cranberry Crunch, and Total Honey Clusters, all of which have 100% DV of calcium per serving!
--Calcium-fortified orange juice
--Calcium-fortified soy milk
--SunnyD with Calcium (most SunnyD products don't have calcium, so look for the one that does if your child needs extra calcium in his diet)
--Instant oatmeal
--Calcium-fortified bread or English muffins
--Calcium-fortified drink mixes such as Pediasure or Carnation Instant Breakfast
--Other calcium-fortified breakfast cereals, including General Mills Golden Grahams (350 mg)
Daily Calcium Needs
-- It is also important to understand how much calcium kids actually need.
The Food and Nutrition Board of the National Academy of Sciences recommends:
500 mg a day for kids who are 1 to 3 years old
800 mg a day for kids who are 4 to 8 years old
1,300 mg a day for kids who are 9 to 18 years old
Keep in mind that calcium's percent Daily Value (% DV), which is a guide to how much of a particular nutrient you should get each day, on food labels is based on the adult requirements of 1000 mg a day. So a cup of milk that was 30% DV for calcium, would be equal to 300 mg of calcium, which would actually be equal to 60% of a toddler's calcium needs for the day. But it would be only about 23% of a teen's calcium needs. That means that you can only really use the % DV as a guide to how much calcium your kids are getting from the foods they are eating each day.