It depends on what kind of games they want to make and what they hope to get out of it.
A simple side scroller? Gamemaker.
A more-advanced 2D game? Gamemaker or Unity.
A 3D game? Unity.
An FPS or other first-person game? Unreal.
Programming skills that will be useful for a career in programming generally or in game development specifically? Unity or Unreal.
With Godot, you'll be perpetually waiting for Godot to finish up and polish the 30% of features you actually want/need. I gave Godot 5 years before I gave up on it. Unity has announced, implemented, and abandoned features in less time than it takes Godot to finish that last 30%.
A simple side scroller? Gamemaker.
A more-advanced 2D game? Gamemaker or Unity.
A 3D game? Unity.
An FPS or other first-person game? Unreal.
Programming skills that will be useful for a career in programming generally or in game development specifically? Unity or Unreal.
With Godot, you'll be perpetually waiting for Godot to finish up and polish the 30% of features you actually want/need. I gave Godot 5 years before I gave up on it. Unity has announced, implemented, and abandoned features in less time than it takes Godot to finish that last 30%.