I didn't realise VS had left, but hopefully she'll pop back.
I know a little bit because my DD suffers from them, and I know what VS would have gone through - I thought my DD had died in my arms. My heart nearly stopped. I couldn't speak - I ran out into the street and a passerby had to call the ambulance.
The amazing docs at the hospital were so helpful. They explained that the convulsion itself is not actually very dangerous - it's more like a safety mechansism. They ALWAYS keep in 1st time febrile c's overnight, but more because it's an opportunity to educate the parents or carers about what to do next time. In reality, there's no need to hospitalise (except DD had a severe urine infection so they did keep her for 4 days until this was cleared up).
They told us if it happened again, we should feel able to call and ambulance if we wanted to, or bring her in - whatever we felt most comfortable doing. But they stressed that it wasn't necessary for DD, it was more a support thing. They gave all the advice about how to bring down temps effectively and swiftly in the future.
They mentioned genetic predisposition and both of us looked blankly at them. It was only when we informed MIL that it had happened that she very casually said "oh yes, DH used to have those". We were a bit WTF? But it was oddly reassuring to know she "fitted" the brief, so to speak.
We are now just very liberal with the calpol at any hint of temperature.
We were completely ignorant of FC's before DD had one, and I suppose the reason I'm posting here in such detail, whilst shamelessly not having read more than a handful of the posts, is because if it means even just one other mum isn't convinced they've lost their DC when it happens, and can recollect the information on this thread, then that's something.