In youth football, you do not have to worry about complicated passing offenses. The defensive end's job in youth football is generally to contain the offensive running game and turn the play back to the inside. Any time the ball goes outside of the offensive tackle, the defensive end must be able to get off of the block and make the play.
Whether you use a four-man front or a five-man front, the defensive ends are responsible for containment, which means that no one running the ball can get outside of them. To hone this skill, have the defensive end attack the outside shoulder of an offensive lineman. His hands should go to the outside shoulder and armpit of the tackle to control him. Do not have the defensive end rush upfield, as this leaves too much room inside for the running back to run through. Instead, have the end practice staying on the line of scrimmage with his arms locked out to control the tackle. When he sees the ball carrier, he should throw the tackle to the inside and go make the play.
Double Team Drill
In youth football, most teams use double teams on the tackle when running a sweep to his side. The tackle and tight end will double the end to get to the outside of the defense. Teach your end how to defeat a double team. He should never try to go around the blockers. Have him line up on the outside shoulder of a tackle, with a tight end outside of them. When both blockers come to him, the end should try to drive a foot between the blockers and turn his hips to get skinny and slide between the linemen. Once they turn their shoulders in toward each other, the end has won. At times in the drill, the end will try to step through and be unable to. If this happens, the end must go to the ground, pulling both linemen down on top of him at the line of scrimmage to create a pile in the hole.
Young ends need only two moves on a pass rush. In a one-on-one pass rush drill, or against stand-up dummies, have the end attack the outside shoulder of the tackle. He should run upfield, leaning into the tackle and dipping his inside shoulder, ripping his inside arm up through the armpit of the tackle while curving toward the quarterback. After he makes this move a few times, the tackle will begin to rush backward to cut him off. The end should rush upfield for four steps, then plant on his outside foot and run inside of the retreating tackle, dipping the outside shoulder and ripping the inside arm of the tackle.