@Abby, I agree with ThePancreanator on increasing the protein and jettisoning the cheap carbs. Protein and fat will satiate his appetite, while carbs will increase it. That’s just the biology of carbs, fat, protein and veggies. Carbs require loads of insulin, which is a fat storage and hunger enhancing hormone. So I limit carbs significantly and don’t get hungry as much.
My suggestion for snacks includes: Avocados cut in half with salt, jumbo hard boiled eggs, handfuls of almonds or walnuts, string cheese, and hummus with vegetables to dip. If he has a good protein/fat/veggie based breakfast, he won’t need a lot of these snacks before or after lunch.
For breakfast, I pre-make a large 6 egg omelette with spinach, cheese, and chicken or roast beef. I cut it into individual meals and let cool. Each serving can be placed in a ziploc bag to go or a plastic container. I easily eat this on the road, cold or hot.
For lunch, he could bring a colorful salad with a variety of peppers and veggies, along with chicken, roast beef, or salmon, or a meat and vegetable dish that can be either eaten cold or heated in the microwave. My favorite is stir fried ground beef with onions, broccoli, artichokes and marinara. Great for lunch or dinner, but you need a cold pack. If you have a Trader Joe’s near you, their Mexicali salad makes a nice starter salad.