addled parent
Might be rough on battery life, but perhaps pulsing an SOS with the flashlight?
It is rough, but I like it if it's "toggled" when needed.
If the person doesn't respond to an "Are you conscious?" alert, maybe allow responders to "toggle" certain actions like the flashlight you mentioned.
A meshnet for communicating back-and-forth between devices. Permissions might be tricky though.