How wonderful of your cousin to be able to help out!
I kind of like the challenge of trying to make healthy, inexpensive meals that my kids will eat. We also eat a lot of vegetarian meals, which is a cost savings. Vegweb.com has a lot of easy meals with not-complicated incredients. I've recently started making an occasional trip to Aldi to pick up things like cereal and canned veggies - so much cheaper!
What sort of foods do you like? Here are some a few ideas - just let me know if you'd like more detailed recipes (or you can look online for recipes.)
Chana Masala and rice (we have a very easy version, basically chick peas, onions, potatoes or sweet potatoes, coconut milk, curry, ketchup)
Dahl with rice (lentils with curry) Also make chick-pea fritters with chick-pea flour that I got from an Indian market. Yummy, and only 3 ingredients: flour, water, onion.
Mexican-style lentils served with tortillas
Refried bean tacos with corn tortillas, avocado, etc. We have this at least once a week. You can also serve grilled meat or fajita mix if you want.
Vegetarian/bean chili
Veg chili leftovers: fill a 9 x 13 pan with taco chips. Spoon leftover chili over the chips. Add a can of corn if desired. Sprinkle with cheese (chedder, mexican mix) bake at 350 until cheese melts - 15 min. or so. Serve like nachos with extra chips, sour cream, etc.
Fried rice. The secret is to scramble the eggs on the side and add at the end. Use lots of veggies and some fried tofu or diced chicken and don't use too much oil, and this is healthy and pretty fast to make.
Enchiladas or mexican casserole. Lots of variation, but start with those cheap 5/$1 corn tortillas and some beans and on-sale light cream cheese.
Crustless broccoli quiche.(note - most online recipes use way more cheese than you need.)
"breakfast for dinner"
Pasta bake with veggies and some sort of protein - meat or meat substitute and/or cheese.