True. And a few other things.
People keep mentioning. "Why don't you have the kid run next door to the neighbor and get them to get help?" Last time I checked, if they're smart (and independent) enough to go next door for help, they're more than capable of hitting a panic button. Secondly, hitting a panic button, dad checking the cameras, and dad reacting, is all probably going to happen a lot faster than kid running next door, kid ringing door bell, talking to neighbor, neighbor coming over, neighbor deciding what to do.
On the same token, the panic button ->dad ->calls neighbour chain would likely get the nearest adult to the scene a lot faster than having the kid heading outside. Safer, too. Much better to have the kid inside with an epileptic than outside running around in a panic. What if the nearest "friendly" house is their friend's house across the street? In a panic the kid's not going to be looking both ways.
From the sounds of things, his wife is perfectly capable of taking care of things 95% of the time. If she was having daily seizures, he probably wouldn't be leaving the house. You don't need live-in care for something that may well only happen once a week or less. Instead of viewing this as an attempt at delegating all caretaking responsibility to the kid, think of it as establishing multiple fail-safes.
We know he's got bunch of cameras that he watches on a regular basis (but not continuous). Given that he's technically inclined, and that, from what I gather, many people with epileptic seizures can recognize onset symptoms, (not all sufferers, definitely not all the time, but at least sometimes) there's probably decent chances that they've rigged up something that the mother could use herself. Maybe just a speed dial, but possibly other things. If not, then the various ideas of using exercise bands and accelerometers might make a very good layer of redundancy there, too.
Personally, the idea of having a sensor-rigged cupboard with a big stuffed animal in it, and telling the kid to take mom the stuffed animal when she's in trouble sounds like a great idea too. Great padding to have between an epileptic and any potentially hard surfaces, although unlikely a kid would be placing it optimally.
Frankly, giving one's kid a panic button that sends a message to Dad seems like a really good thing to have, no matter what the situation at home is. Honestly, it isn't exactly that rare of an occurrence for the sole responsible adult at home to have some kind of accident where it would be *very* useful for the kid to have some way of summoning a responsible 3rd party, whether it be a neighbour or relative or whatever.
Lastly, just because he hasn't laid out every last precaution and detail of his family's life is no reason to assume that they're being negligent, that she's having daily severe seizures, or that they're pinning all their hopes of safety on the kid. We don't need to know all that. He simply asked for advice on a single, specific solution to a specific element of his situation. Let's help him out on that, shall we?
Some quick links that a google search turned up:
First one is an instructables video, the last two are commercial options, one for phone software, the second for an actual device.