Any hints as to what that offence might be?
And why do you feel it might be necessary - Causing death by dangerous driving already carries very similar sentencing to manslaughter (as it should, since that is what it really is).
IF the driver's claims are true (big IF - which is probably why the re-arrest), then how on earth can you make having an epileptic seizure for the first time into an offence?
Regardless of any other penalties, if she had an epileptic seizure, then she automatically loses her licence, and will not get it back unless and until a doctor certifies that there is no danger of further seizures.
Not true, in the UK at least.
Not all fits/seizures are as a result of epilepsy.
One fit/seizure due to a head injury, with no previous diagnosis of epilepsy will result in you having to surrender your licence.
A year seizure free, whilst awake, and you can re-apply for your licence. The doctor/specialist will certify that you have been seizure free for the year. Not that there is no chance of any further ones.
No doctor, or specialist, can ever say there is no chance of further seizures. Nor would they.
Seizures need to be under control, medication or otherwise, or occur only when your asleep.