My son consistently makes contact, however he does not hit through the ball and his bat angle at contact continues on a downward plane instead of a even plane. He always hits grounders and never/seldom line drives. Other than telling him whats happening and demonstrating the proper technique, I can’t seem to get him to adapt the proper mechanics (I think this is where I was going with the Dad thing!) Anyway, are there some drills you can recommend that might creat a muscle memory for the proper mechanics in hitting through the ball and the proper swing plane?
Your son sounds like he has the correct idea of starting at a downward angle. In his toss drills, and off the tee, have him start finishing his swing shoulder high. As you stated the swing should level off, if you work on the finish, he should level the swing off. Make sure he is not rolling his top hand too soon, the top hand should not roll until well after contact. Do some tee work, move the tee about 5-7 inches in front of where he would normally make contact. If he continues his downward angle he will not be able to make good contact. He will have to level his swing in order to make contact. Have him try to drive the ball back up the middle, keeping his hands going through the contact plane.