The third common cause of a drop attack is a seizure. We tend to think of seizures as the epileptic spells young people sometimes have. But they can occur later in life, too, usually as the result of an otherwise undetected stroke. In this case, the seizure isn't accompanied by jerking motions, but instead may show up as a drop attack. Again, it's essential to make the right diagnosis, usually with an electroencephalogram.
Seizures are usually completely controllable with medications.
These three different conditions are the main causes of drop attacks. But there are others, such as low blood pressure or low blood sugar. These are less common, but should also be considered. I encourage you to persuade her to check these things out. You don't need to resort to a high-powered specialist, at least initially.