Playing style of a Child

I agree with Ghost; first that many very good players have defensive styles, and; second, that it is too early to talk about style. Also just let him enjoy it the way he does. 

Play a series of games where they have all their pieces but you have only K, Q and the pawns. Your child will learn to enjoy chasing the Q around the board and will become more aggressive. Be prepared to lose lots of games but win when you can, don't throw any of the games.

See what happens.

"Let the little children come unto me" ... 

https://www.chess.com/coaches

i love to teach my kids how to play chess

Playing kids is creepy because they play creatively.  I remember every single game I've lost to a clever kid. 8)

LOL XD