Is she on any sedation? Commonly people on ventalators are sedated so she would not be awake. If she is not on sedation it could be that her body is overwhelmed and exhausted. Also she may still be having seizures that are not obvious to the eye. She may have experienced a period of time without enough oxygen to her brain. That could cause an abnormal EEG. And cause her not to wake up. Is she on any anti seizure medicine?
Well it sounds as she is being treated throughly. Decreasing her medication will hopefully help. Hopefully they will do another scan of her head due to the fact that if she had another stroke caused by a clot that would not show up on a scan for a couple of days. If she was on powerful sedation, it may take a while to get out of her system. Especially because of her age. Again, I hope this helps and let me know if you have any other questions.