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A few ideas:

a) One tough-love way is to make him play against strong pieces with minor pieces. Run a few drills like that on an empty board with the pieces and two kings.

For example, two rooks vs. a queen. Then graduate to 3-4 minors vs a Queen or two rooks.  He'll obviously think he's losing and that the stronger piece wins all the time but after you show him how better co-ordinated weaker pieces can do more damage than one strong one, he'll start appreciating co-ordinated pieces more.

b)  One more way to get him to figure out how important it is to start a game without the queens.    Kids get into this "queen" thinking early on and expect quick mating attacks against their peers. Take the ladies out and they'll be forced to grind into middlegames and endgames where they need to make all their pieces do the work.

c) Another idea is to impress upon the young one how covering squares is vital. Practicing a 2 Bishop vs. King mate is one example.  You might even consider having him play bughouse helps because it helps one quickly identify  holes and weak squares that usually mean instant disaster.