I enjoy meatless chili verde, which is basically just chili verde without putting the pork into the salsa verde.
Does he enjoy substitute meats like boca burgers and the like? I personally don't like the flavoring of them, but if he does then there's all sorts of things you can do with them like make boca "meat"loafs or casseroles.
Ooh! Tostadas! Tostadas can lend themselves to an excellent and really filling meal, I find, and you can make them all sorts of ways. They're basically a fried tortilla that you can cover with whatever you like. I personally prefer a combo of frijoles, lettuce, tomato, cheese, and homemade salad dressing, but there's many things you can do with them.
You could try making breakfast foods, like pancakes and waffles and french toast, some hashbrowns, bisquits, a little fruit juice, maybe a bagel. Always a filling meal.
Quesadillas are good too, you can add extras like peppers and tomatos and things.
I'm also told, and this is just hearsay because I'm too afraid to try it yet, that fried apples and onions is delicious. Apparently it was a popular meal for pioneers who ran out of meat.
Does he like cucumbers? You can slice a cucumber really thinly, spread a tortilla with cream cheese, fill the tortilla with cucumbers, lettuce, and whatever else you'd like, wrap it all up, and there you go!