The term "junk miles" comes to mind. Easy should be easy but you need to get his heart rate to a point where it is a certain percentage of maximum.
Find out if he has a heart rate monitor or if his parents will spring for a watch with that option. If not have him run a few laps take his pulse if it's too low tell him to speed up and keep checking to you get in the correct zone. That's his new easy run pace.
The other issue could be is this kid really doesn't care about his times.
You have to coach to their level of desired result NOT your level.
There's more to coaching than giving workouts. Any monkey can give out the workout for the day. Chop chop earn your money big guy.