Just got off the phone with her. If I understood her correctly they're releasing her today and ruled out Epilepsy and are fairly certain she has a heart condition. They want her to see her doctor so he can refer her to a cardiologist because it'll be easier that way.
What I don't understand is this, the hospital she is in is supposedly renowned for being one of the best cardio care facilities in the Tampa area. Why wouldn't they just have her do all that there while she's admitted?
That might be very good news. At this point it's impossible to say what the problem is, though it definitely doesn't sound like epilepsy. Depending on her age, weight, medical conditions, medication/drug history, diet etc. this could be a number of things... many of which are benign.
The reason they're referring her out is probably because they have the diagnosis (orthostatic hypotension), but she needs to see a cardiologist for treatment. She may also need further testing to determine the underlying cause of her orthostatic hypotension. For example, if she's 23 years old, 95 pounds and has been vegetarian for the past ten years, she may be severely anemic (in which case, changing her diet will cure her). Drugs or medications may cause orthostatic hypotension as a side effect.
And while there may be the few rare, scarier causes for orthostatic hypotension, most likely they would not have discharged her if they thought she were in imminent danger. They really should have given you more information, but perhaps they did not do so because they wanted the cardiologist's opinion.
Anyway, good luck! This situation is very, very common and is rarely going to be anything that isn't treatable.
e: Just make sure she doesn't make sudden movements, like jumping out of bed or out of a chair. Whatever the underlying cause of her illness, it's causing her body to be unable to increase her blood pressure. So, what happens is when she stands up, her pressure drops, pulse shoots up, and she may get some scary symptoms like blurred/blacked out vision, or she may just pass out. You want to make sure she doesn't fall and injure herself. Sometimes people will also fall when they're getting up from going to the bathroom, or while taking a shower (you can put a small plastic chair in there).