Greetings sirenamax,
Thanks for visiting the Apple Support Communities! It seems your son's iPhone has accessibility features enabled, and now he can't unlock the device.
It appears VoiceOVer was enabled. Check out the information in the following article for disabling VoiceOver:
Turn on and practice VoiceOver on iPhone - Apple Support
Important: VoiceOver changes the gestures you use to control iPhone. When VoiceOver is on, you must use VoiceOver gestures to operate iPhone.
To turn VoiceOver on or off, use any of the following methods:
Kind regards.