What kinds of children's stories has she written? For what age group, like 5-8, 8-10, 10-14? How long? 500 words? 1,500? 30,000?
You're going to have to educate yourselves on the children's book business. I recommend you check out
The Purple Crayon website, which has a ton of great information. Read all of it. Learn what and what not to do. Follow the links and read those too.
Visit the bookstore. Compare what you've written to similar titles on the shelves. Talk to a children's bookseller to see what's popular these days. Remember: what was popular ten years ago, what sold five years ago, is different today. Make sure to understand current trends.
Read this book:
How to Write a Children's Book and Get it Published (or any similar book), available at your bookstore and library. While you're there, check out all the other books about writing children's books.
Writing for children and getting the work commercially published is not easy. I know. I tried. My book is still unpublished, and will probably be rewritten sometime in the near future.
Ask all the questions you can think of; it's why we're all here.
Welcome to AW, by the way!
allen