By deleting the Blueprint function that updates the camera pitch based on control rotation pitch, you’ve literally removed the only thing allowing characters to look up or down. You haven’t added similar code in C++ to bring the function over either. But yet somehow, it just works for you?
I don’t think he realized at this point that he deleted that functionality. He didn’t test it, but I’m sure his NPCs wouldn’t be able to aim up or down at this point.