Would she be willing to cook with coconut flour? If so, I recommend this book: Amazon.com: Cooking with Coconut Flour: A Delicious Low-Carb, Gluten-Free Alternative to Wheat (9780941599887): Bruce Fife: Books
It has low sugar alternatives although some of them require special ingredients. I sometimes just sub Splenda - I know it's not great for you, but I only bake occasionally for a special treat so I don't worry about it.
The thing about these coconut flour recipes is that they will taste like coconut, so if you don't like it, this won't work. I made a really good fruit cobbler at the end of summer using a recipe from this book and served it with sugar free ice cream. It was really tasty.