move on to the bigger stuff like C++.
there's no need to take the hard way out if you don't need to, honestly.
once he wants EVERYTHING to be 100% custom then C++ would be a good option, but if there's already a simplified form of game creation available that will fit his needs then he can go ahead and keep using that.
it would depend on preference too but i doubt he wants to make a game quite literally from below the ground up.