You can adapt the basic message in order to try and prevent the child feeling frightened about your seizures. Keep it simple based on the child's level of understanding. Using reassuring words, describe what they may see before, during or after a seizure. If you compare your epilepsy to something they are more familiar with, this can also help. Use plenty of reassuring language. You can end with giving practical information about what you want the child to do if they see you having a seizure. Keep this information simple so as not to over-burden them.
I said to him, sometimes in the morning when mam gets up and she just falls over and it seems a bit silly, well she suffers from something called epilepsy. I don't know if you've heard about that before and it's just where there's a lot of electricity in somebody's brain that just fires off together and they just make you just fall over. But there's nothing wrong, I'm not even sick, but I'll be actually fine in five minutes and I just need to sit in the corner and just put my head between my knees and maybe have a glass of water would be good.