He sounds like a smart lad. Teaching a y to throw righty actually would be the best technique here. But for the sake of argument, propose to him these possibilities:
The Salt Shaker (with back to first base, fling the ball blindly over shoulder)
The Ninja Star (with a whipping motion, propel the ball sidearm and backhanded, like a Frisbee)
The Exorcist Twist (wrench your trunk 45 degrees to the while keeping your feet stationary, then hurl the ball with a standard throwing motion with feet facing one way and head facing another)
The Tasmanian Devil (spin frantically and fire the ball like a sling)
The Boomerang (throw the ball at the pitcher with enough sidespin to make it break 90 degrees in midair and fly to first base)
The Deep Snap (barehand the throw, bend down and whip the ball backward from between your feet)
The Extra Arm (instead of throwing the ball directly to first base, fire it to a charging outfielder who makes the relay to first)
Ask him which one seems the most feasible if the 2B actually has to throw -handed.