L.S.
My husband is vegan and gluten-free. Polenta is great, quick and easy. Brown rice is a stable. He likes daiya cheese and vegannaise (vegan mayo). Earthbalance is a good choice for a butter-like spread. Almond milk is a favorite. Trader Joe's has a great list of gluten-free foods. They make a granola (two flavors) that he really likes. You can also get pre-cooked polenta that is shelf stable and great for in the pantry. Whole foods has frozen gluten free dough that will make it easy for you to adapt a homemade pizza night. Use regular pizza dough for everyone else as the gluten free stuff is expensive. Mexican recipes and Chinese recipes are great as there is not a lot of wheat and you can usually leave out any cheese. Popcorn is a great snack.
It is a hard change at first, but my husband is so much healthier and I have gotten good at making meals that allow folks to pick and choose options at the table. Good Luck!