I have a dairy free DCK. I just don't make any meals with milk in them when the child is present. It's not hard to do at all.
We use gluten free pasta and use sauces that aren't milk or dairy based.
You could use tomato based sauces or vinegrettes.
It's easy to skip the cheese too and serve meats/legumes instead for protein.
Can he have eggs?
My little one is a HUGE meat eater so that helps alot. Mine also likes eggs and beans. Especially navy beans and kidney beans.
If we have to, we substitute cheese with a "cheese" product made from tofu.
I also check this site for lots of recipes and ideas too
http://www.godairyfree.org/