Why is my client having seizures again? What can be done to help?

This, unfortunately, is yet another spirit infestation. You can verify this for yourself. We understand this will be disconcerting to the family, especially with the ongoing prayer efforts, but keep in mind she is the most important factor, and her energy. If she falters in some way, spirits can slip in yet again. That is all too easy, especially with a history of trauma and having great sensitivity as well, such individuals are easier prey because they will be manipulated at night during sleep and many types of subterfuge can be utilized to fool a person into dropping their guard. That is what happened in this instance, so it is not a failing of the mother to protect her child nor the girl herself in standing strong. It is her nature to be energetically aware and quite sensitive and this does increase risks somewhat. This is an innate talent and capability that has many advantages, although this one downside would seem to negate that, but it is only the unhappy situation of seeing a relapse that will prejudice thought to want throwing out the baby with the bathwater, so to speak—that is not necessary nor is it done easily in any event. The best that can be done is to do repeated work to help her when these kinds of symptoms arise should this happen again. In the meantime, you can take care of this quite readily.