Does she bake? I make banana bread for DS and DH (I can't abide bananas), it's a recipe with no sugar so pretty healthy and you can do variations.
I mash 3 very ripe bananas, add 125g softened butter (I've used baking spread to make it dairy free for work and it worked fine) , add two beaten eggs, mix together, at this point you can add some honey if you think it needs sweetening DH and DS are fine without.
in another bowl sift 250g self raising flour and 2 teaspoons baking powder (the bananas need the help) , then combine.
Variations I've done are cinnamon (add to the flour) with chopped dates/sultanas
Almond extract with honey and chopped dried apricots
Replace 30g of the flour with cocoa (you made need a splash of water/milk to loosen the mixture) and then swirl through whole nut peanut butter which ups the protein content.
Bake on 160 in a lined loaf tin for 45-55 minutes
DH likes a slice with a cup of tea, DS with a glass of milk. It's a good after school, before activities snack too.
Other than that, fruit, bread, cheese, hummus, pittas, crudités etc. All easy to grab.
Also wraps to make quesadillas, do you have a George foreman or a toastie maker?
I also today a chicken on a Sunday for lunches, but both will occasionally just grab a leg from the fridge.
DS is only 6 and eats like a machine, I'm going to need a second job before he's 15. He's really active and if anything at the low end of weight for his height so I'm always trying to think of ways to get healthy calories into him.