It sucks, it really does, but the books were never legally hers. If she was employed as a for hire
writer there's a good chance that the ideas weren't even hers, legally speaking. They credit her with the created by and legally that's all they have to do, unless there's something in the contract.
The sad thing is that this is predatory contract stuff is pretty common with the Big 6. This is one of the things I, personally, and +42wd Publishing LLC
hope to change in the publishing world.
Make sure you understand your contract. Make sure you understand it in detail. If you have to, plunk down the $300 to have an attorney review it for you. It's extremely important that you know what you are agreeing to. Make sure the terms are fair and beneficial to all parties.
Please, never let your excitement about getting signed over rule your good decision making abilities. I really don't want to hear / read a story like this about any of the creatives I know.
In fact, feel free to send me a copy of any agreement you have or ask me questions about a particular section and I'll give you my opinion on it. I'm not a licensed attorney but I know how to read a contract and will point out the what it says, doesn't say, potential ramifications and when the contract is being deliberately confusing and or vague.