Mix them into everything. I'm very limited on what I can eat, and can't eat processed foods, so I've had to learn to like veggies. A few ideas:
Stir Fry. Cook up some chicken or pork any way you like with seasonings, add in some noodles, bean sprouts, and veggies. I use wilted spinach, carrots, zucchini, and water chestnuts, but you can use just about whatever. Pour in a bit of soy sauce and/or scramble an egg in with it and you have a great meal.
Veggie omelet. Make omelets and wilt spinach or kale in it. You can also add in tomato, olives, peppers, etc.
Grated carrot meat loaf. Grate the carrots up and add them to the meatloaf- he won't even notice!
Broccoli, cauliflour, and cheese. Melt some velveeta as a sauce or mix bread crumbs and Parmesan for a yummy baked crust on them. I can't eat this but even my dad who refused to eat veggies will eat this!
Lemon Broccoli Chicken - cook up some rice, whatever kind you like- and bake some chicken with a can of chicken soup poured over. Steam some broccoli, cut up a lemon, and voila! Put all of these together and he'll be getting a whole serving of broccoli without noticing.
squash -I dislike squash as a rule so I'm trying to develop a taste for them. Turns out there are some great ways to cook them! Zucchini is wonderful cut longways like french fries, and breaded with breadcrumbs and italian seasoning. Spaghetti Squash can be substituted for spaghetti or put in with spaghetti and tastes just fine. Butternut squash is good cooked like sweet potatos. Does your BF like sweet potato? Make it the same way- bake it, mash it, put a little brown sugar in it, and it is practically a dessert!