I’m not a parent, but going by pop culture, it seems like literally every child has the same fears.
In pre-modern times, I imagine that they’d be sleeping in the same room as the parents, but if modern notions of privacy don’t permit that, seems we could at least design an enclosed capsule or something.
Same with me. Even when the room was brightly lit I would get anxious and would ask a parent to sleep with me just because I was alone, not being able to sleep.