Coach,
I've been letting these guys win for years! I love to hear them talk trash and brag about what a great team they have. It makes me feel good to see these minature adults put so much of there egos and talents into these little imaginary plastic figures. Let the little guys win for a while and just when they think they know everything you clobber them. In your case wait until the little dude turns 15-16 he should be manture enough to handle it.