Many seizures (mostly tonic--clonic) leave the person exhausted afterwards, they will sleep for long periods of time and it is very hard to wake them up for a while. I know that medical care in jail is not top notch, but if Casey was suffering from seizures she would get seen. It would be interesting to know if she has visited medical staff, while in jail, with her complaints of seizures. My gut tells me that she may be trying to copy her letter friend with medical complaints of her own, but I can't know for sure. If medical staff thought she suffered from seizures, most likely they would have put her on anti-seizure medications (depending on the type and severity of her seizures).