Cousins phone is suspicious, thoughts?

[A Former User]

Came home and my cousin told me about it, I thought it was normal, so I googled it and it said it’s just the front view camera light being turned on for Face ID recognition, and should only be on during Lock Screen.
Before I started recording, however, when my cousin turned on his DS camera to show me, that flashing light kept flashing and was on even when the phone was off, and off of the lock screen and instead on the home screen.
However, when I started recording, telling my cousin to let me record it, it stopped doing that and instead only turned on and flashed when at the lock screen. Since it only stopped doing that while I was recording, I have no evidence that it was doing it beforehand