It sounds like he isn't moving his feet very well. try this:
1. Have him charge everything - no matter how hard it is hit. This will give him confidence in his hands and feet.
2. Make him count the hops aloud. This will have him concentrate on something other than standing flat footed and waiting on the ball.
3. Have him play EVERYTHING off his left ear prior to breaking down into his fielding position. This will give him better angles to not only read the hops, but get his momentum going to 1B (which will allow him to get through the ball).
4. Finally, have him work his feet to get a good hop. Similar to #3, but this relies on forward and backward movement.