Duncan has his first episode when he's barely five. It is, to that point, the most terrifying few minutes of Celeste's life, stealing the spot from the moment she woke up in a puddle of blood at 18, losing their first child and eclipsed only by the precious few second between seeing Lilly lying beside their pool and the realization that the fear was too late because the worst had already happened.
She was alone with the children at home. It was during that odd time when they had technically crossed the line between upper-middle class and rich but didn't really live like it yet; before two full time house keepers when she thought acting like the perfect housewife would entice Jake to act like a husband. Jake is spending night and day at the office (screwing Lianne), perfecting streaming video and preparing the company for going public.
It starts with a giggle from Lilly. The kind that lets Celeste know that her daughter is about to do something that will land her in trouble, but instead of the expected crying sniffles from Duncan or another victorious giggle from Lilly, her little girl screams.
She rushes the small distance from the kitchen to the children's play area to find Duncan on the floor. At first she thinks it's some kind of tantrum. Then she sees the blank look on her son's face and the confused terror on her daughter's and realizes something is really wrong. As she fumbled to call 911 Duncan calms down to placidly blank instead of violently and she sits next to him, numbly making sure he continued to breathe through the wait for the paramedics.
Lilly is too young to ride in the ambulance (and too easily bored, really, to come to the hospital anyway) so Celeste has to let her son travel alone while she frantically calls around to find someone willing to watch Lilly, then drives herself.
Jake arrives after the scans, just in time to act as the worried father as the doctor tells them their son has had a seizure, but they don't know why. It takes months of tests and specialist to come up with a real diagnosis (and years, if she's honest to find a mix of drugs that is anywhere near right).
For the rest of the year and into the summer Lilly gets a Nanny, and Duncan gets tutors, appointments and classes, alternating being poked and prodding and "keeping up" with his mostly unseen classmates.