I agree with everything said above, also, when you are both at the baseline, pin him into a corner. Hit everything to one corner (probably backhand), and make him commit the error. A pusher's biggest weapon is their speed, they like to run around a retrieve balls. By keeping him in one corner, you are taking away what a pusher likes to do best. Also, when you get the opportunity ball to take control of the point, it is crucial that you have very specific, safe targets. If you try to hit away from the kid, then you will start spraying balls.
Hope this helps - Good Luck!