My HUGE red flag was "his coat and backpack were still at school" because who thinks of that crap???? Maybe there was a male chaperone, maybe not. And how did she know there were no men on the chaperone list, and why would she leave Kyron there if there was a stranger on the chaperone list. High chaos, no coordination... yeah... Smell hinky.
Hmmm...these are 2 emails that are obviously parts of ongoing email conversations. So we don't have the full context.
Maybe she didn't find out until after Kyron disappeared that there wasn't a male chaperone on the lists. Maybe (if she's telling the truth--and the kids on FB were too) the guy right then acted like he was supposed to be there, everything looked normal to TH and so she left. She only got a brief exposure to him. The kids got more, which may be why some talked about a "creepy guy."
If he was having "absence seizures" that might explain his timidity in some ways. That kind of stuff would be scary to a kid, especially a smart kid who would know something wasn't right.
As for KH not knowing, based on prior statements, that wouldn't surprise me. After all, he said TH had been depressed, doctor said to keep an eye on her, but when asked about her medications he didn't know. As many of us have said, there seems to be a lot of disconnect in the communications with all the parents.
And if DY only had Kyron on weekends, and his seizures had only started, she might not have noticed them yet. After all, they might not have happened often with her right there. A grand mal can't be missed, but something like a mini (just from what I read at the Mayo link) could be subtle.
JMO. I'm just tossing out ideas.