any creative dinner problem solvers out there?

Hi! I could use some brilliant dinner ideas. I have 3 kids; the oldest (16) is a vegetarian. The middle one (13) has recently diagnosed with allergies to wheat, peanuts, and corn. These are not the life-threatening sort, thankfully, so we don’t have to eliminate every trace. but he gets stomaches and headaches, so the goal is to decrease his intake as much as possible. I don’t mind cooking separate things some nights, but I could really use a few menus that would suit everyone. Anyone have any ideas? I would be very appreciative!