We are a nearly vegan household, so do most of our cooking and baking without egg and dairy. Most any vegan cookbook or website will be helpful. We like Vegan Family Favorites by Erin Pavlina, Vegan Lunch Box by Jennifer McCann, and cookbooks by Dreena Burton and Sarah Kramer. And http://kidsarevegantoo.blogspot.com/
When cooking and baking, eggs can be replaced with Ener-G, fruit purees, tofu, or ground flax seeds mixed with water. Wheat flour can be replaced with an alternate flour - rice, barley, etc. Sprouts offers a fair amount of gluten-free pre-made products (cookies, breads, cake mixes, etc).
After some time of practice and getting used to slightly new things, he will still love those favorites - my family hardly notices when I cook or bake vegan. It's delicious!
The trickiest part is eating out and at other people's homes. But they will soon learn where to go and what to ask for, as well as what to bring. :)