Reddit mentions of Appetite for Reduction:: 125 Fast and Filling Low-Fat Vegan Recipes

Not OP but I recommend Isa Chandra Moskowitz's cookbook Appetite for Reduction. All of Isa's recipes are good (seriously), and this book is aimed specifically at weight loss. Here's a link to a few recipes from the book. And if you're not in a position to buy the book, I'm sure you can find other recipes from it online!

Though I have not personally cooked from them, you might want to check out Quick Fix Vegan or the 30-Minute Vegan Books (1, 2, 3, 4), which are geared toward making food in 30 minutes or less.

My personal favorite book for when I'm looking for something easy and relatively fast is Appetite for Reduction. Though the title doesn't suggest it, the author notes that many of the recipes can be made in 30 minutes or less. It's a low-fat (not fat-free) cookbook, though, so that may not strike your/your SO's mom's fancy. Still, I've made lots of tasty things from it, and I'm not a dieter. It also has cute veggie illustrations.

I know that the end of Appetite for Reduction Isa goes into how to plan out making "bowls" such as the mediterranean bowl consisting of bulgur, roasted cauliflower, chickpeas, and a dressing that can be made following the recipe in the book. There's also some good sandwich suggestions which are made up of various recipes in the book.

The book can also be really good for weight loss since it breaks down the nutritional content for each recipe. IIRC, the book is also focused on less calorie dense items as well (hence the title).

edit: Just checked and the Veganomicon has a few meal suggestions as well.

I really love the cookbook Appetite for Reduction. It sounds like exactly what you're looking for--low fat, quick, healthy, and easy.

It's a vegan cookbook, which is kind of nice because it eliminates some high fat foods like cheese and eggs. But if you're not a huge fan of tofu or tempeh you could always cook some chicken breasts instead.