I have not trained someone with this but my mother had narcolepsy. There are a couple of basic things I would suggest.
First, recognize that there are some risks. It is wonderful that you want to continue with her, and good for her overall health to continue with you. However, she is right that the cataleptic piece could create the possibility for injury. Moreover there is a brain effect that could affect the training relationship. And there is the possibility of her falling asleep as she works with you. My mom would fall asleep in the middle of reading us a book.
I would suggest you do some research with the sleep foundation.org (I think that is right) and get some basic information on the condition. Then, send a letter to her physician outlining what you have done with her, and asking for feedback on whether training would continue to be helpful for her and what sort of adaptations they would recommend. Also find out what medication she will be on and what the side effects might be. Some of the meds do have effects which you might want to watch. You might also want to consider extra CEC training on special populations to help bolster your professional credentialing, if you do not already have some specialty certification.