I just want to let you know that I know EXACTLY what you are going through. My son had a seizure at around 4. It wasn't as scary for me because only my mom witnessed it. We weren't 100% certain that it was a seizure and I had completely missed it. I called his pediatrician and he just had us come in. He checked his vitals and did an in office EKG. They said he was fine but set us up with a neurologist. He got in, had an EEG and all was normal. They said that people can have 1 unexplained seizure and have nothing wrong with them at all. We were supposed to just wait and see but it most likely was a fluke type thing.
Well, a year later, he fell to the floor limp with stiff limbs, lips blue making an aweful noise like he couldn't breath. SCARY!! I called the ambulance and they took him to the hospital. Same thing happened. We were released and got an EEG a few days later. Again normal. This time he was diagnosed with seizure disorder (Epilepsy). Started on medication, however I decided later that medicating him 2x a day was not worth it. They didn't even know if this medication would work for his seizures.
He still continues to have a seizure once every year. It is still just as scary as the 1st time. My heart breaks every time it happens. By the 3rd one I asked the hospital to check his brain. By then I had read more up on it and wanted a tumor, etc ruled out. He sees a neurologist at CHOP and has an EEG after every seizure. They are all still normal. The doctor does not think he should be medicated unless his seizures are more frequent. Which I do agree with although its hard to think clearly right after a seizure. You almost want to just give him something to "fix" it. According to ther doctor, he could grow out of it. He could never have another one again or he could start having them every week. There really is no way of telling for sure. But he did say that a lot of boys grow out of them around puberty.
He also did say that I coould do an MRI to see if there is a small abnormality. But he said that My son would have to be sedated because of his age (9) and that he doubts they would find anything. Even if they did, treatment would be the same. I guess that would only be helpful if he had frequent seizures.
I hope this information helps. Seizures do run in my family. My sister has seizures (normal EEGs), my mother does too (also many years of normal EEGs, just finally showed something a couple years ago), and my daughter had 1 seizure ( must have been a fluke one, keeping my fingers crossed though).
Good Luck! You can contact me anytime if you have any questions.
I also wanted to add that seizures technically are not harmful as long as they do not last longer than 5 minutes. My son has a prescription for a medication that I am to administer if it were to be needed. Although since none have lasted that long it is unlikely that they would start. Just thought you might like to know. I am not sure how long your sons lasted but I was a little concerned since you said he didn't "come to" till the ambulance ride. I have one tube here at home, and one tube at school.