Does he take any pre-game batting practice? Perhaps some pre-game tee, side toss and live pitch BP can help. Also, is he using any type of relaxation technique? If not, prior to stepping into the box, he should pick out a small point on the bat (small number, letter or mark). While focusing on that point, take a deep breath then exhale. This will help him clear "inside or outside noise" that may be affecting his concentration. Reset with this technique if he goes deep into the count, fouls off pitches or starts to feel nervous during the at bat. Also, make sure he has a good game plan for his at bats (should not be taking decent first pitch strikes etc.). Hopefully this helps.