Ok, so make a list of the foods you both still CAN eat.
I'm guessing that there are no other food allergies here? So this means you can use rice, corn, qunioa, millet, etc, and their flours and flour products (tortillas, pasta, etc)? Eggs and dairy and nutritional yeast (grown on beet molasses, not barley- some yeast isn't gluten free!) and nuts, and all kinds of fruits and veggies and beans?
Rice flour can replace wheat flour in thickening sauces and holding together bean burgers, without making any changes to recipes. For breads, pancakes, waffles, and muffins, use a gluten-free recipe (you're unlikely to find meat in gluten free baked goods recipes.) Any "beans and rice" dishes can be followed from vegetarian recipes with minimal changes.
Many processed "fake meats" use wheat gluten as a protein source, but tofu and TVP are gluten free (just be sure to check all packaged products to make sure there's no gluten contamination.)
You need to read labels carefully on things like soy sauce, salad dressings, etc. You need to replace (or have somebody other than DH finish up) any opened jellies, peanut butters, etc, that may have been used on gluten breads or crackers- a few crumbs in the container can sicken him. You may want to replace spices as well, if there's any chance that flour got into any of the containers.
I also strongly suggest that you get the kids tested for celiac- it's hereditary, and you could save your kids a lot of pain if it's diagnosed early.