How do I get out of 3rd person on a PS4 controller?

I might not be able to help since I play on Xbox but I'm here to try. Try pressing up on the d-pad. If that doesn't work go into options on the pause menu and look for the controller settings, go into there and see where the buttons are mapped, find out where the pov button is, then change that to the button you would like it at. Hope I helped!

By default it is L3 (push the left joystick into the controller, yes, push it down). I think this is very annoying personally as I would constantly accidentally activate it in the minigame days so I would suggest changing it and maybe making L3 a sprint button or just disabling it outright, just preference.

Pressing this button will cycle you through 3 POVs, so just keep pressing it until you get it how he likes it (first person in this case).

If this button doesn't work go to Settings > Controller and see what it says it is set to and change it if wanted. If it is unbound (not set to anything) set it to something.