Jim
While it's not necessarily great news about the Epilepsy diagnosis, still it could have been far worse. At least they have a positive diagnosis finally and that can be treated.
If it's any comfort to you, one of my classmates in HS had Epilepsy yet lived a full and active life. In fact he was one of the more popular kids, had plenty of friends, and did just about anything he wanted with the exception of being able to drive a car. His seizures were under control with the meds and he went on to be active in sports. Don't remember him ever having a seizure at school, nor was he ostracised for it.
He always displayed a positive "can-do" attitude which it seems that Katie also has. So she has that going for her!
Cheers,
RR