He just needs to focus on his weak points. He just needs to do less chest work and more leg and arm work. Like squats, deadlifts and I like dips and chinups fore arms, maybe some isolation movements if he fills like it.
If he is after a overall muscle size growth he should do 8-12 reps. If he wants to tone he should 12-15 reps focusing on his weaknesses while continuing to work on strengths. But also stretch the stronger muscles