I do feel that an adult who 'doesn't cook' but has chosen to spend his life with a veggie could have a coup;e pof meals a week without meat. Tell him to have a ham sandwich at lunchtime on the meat free days if he's feeling under meated.
If you are going to try him on some veggie dishes, I would go for hearty tagines, stews or curry with lots of flavor naturally and fling with chickpeas/lentils etc.
Here are a few ideas that have all the same elements apart form the protein, and use the same sauce/marinade.
Chicken tika for him, panner tika for you. Serve wiht rice and salad and a daal if you can be bothered. Different 'protein' same marinade and everything else.
Piri piri chicken for him, butternut squash and haloumi piri piri skewers for you (or just done in a small roasting pan if you can't be bothered to skewer).
Greek lamb skewers for him, greek marinaded veg skewers for you. Rice or new pots, and greek salad (leave out the feta and put that on your salad separately).
Argentinian steak (tofu for you) with chimichuri, sweet potato wedges and greens.
Butterbean and tomato stew - with chorizo diced up and fried and added to his portion at the end. Serve with crusty bread.
Some kind of potato hash with an egg - can add in diced nad fried chorizo or bacon lardons to his portion if you must.
naturallyella.com/smoked-paprika-red-potatoes-and-egg-bake/
Baked potato with ratatouille, with cheese on top for you and chicken breast for him.
Anything with veggi/normal sausages.
Thai green veggie curry, serve with rice and with do fish or chicken for him on the side and you just have more of the veggie curry or do some tofu in the oven whilst you're doing his chicken/fish.
Some kind of meatball based meal - same sauce and carbs etc just plop on the veggie/meatballs on top (v easy if you oven bake them). Can make nice veggie ones yourself or for an easier meal buy both meat and veggie ones ready made.
I bet he wouldn't even know there wasn't meat in a good veggie chilli with quorn mince and lots of flavor.