I used to take mine to the cage - but I had to wait for him to ask for help. Any unsolicited suggestions usually got a version of "I'm fine...leave me alone"
Go to the 75MPH tunnel...set the plate up so the pitch is on the outside corner or an inch off the edge. Work on hitting line drives into the opposite field net i.e. the right side for Righty and left side for a lefty. Focus on staying in and driving through the ball the other way. Stay positive - with a lot of "that's it", "good", "feel better?" kind of chatter when good contact happens. If they get frustrated then come with the "battle", "gotta stay with it" or my favorite - "you know how to hit".
Then reset the plate so the ball is over the middle and work on driving it right back at the machine.
Do not leave the cages until he is clearly feeling better than when you got there even if it takes 200 swings.
When the game starts look middle out and drive the other way or back up the middle. Do not try to pull the ball.
It usually did not to take long for line drives to return - and with them confidence - end of slump.
