What Causes Sudden Seizure And High Fever?

I am in my 20's and I have trust issues with guys because of previous relationships. The guy that I am talking to now has a five year-old daughter that he said had her first seizure the other night because of a sudden high fever. He also said they had to resusitate her in the ambulence... what made it seem so strange to me, was that they came home from the hospital that morning, (so everything supposedly occured in less than 12 hours). Is this something that can really happen and I'm just being paranoid? Or does this seem like a stretch? Thank you!!!