Growth Stunt, working out

Hey if a teenage 15 and a half of age starts to work out in the gyms, but he does not want to stunt hes growth for sure, what should he do.

He told me that he plan to only do repititions, like probaby bench pressing 50-100 reps (bar only) of 2 to 3 times, or workin out arms with 15 pounds but with reps. will this work out stunt his growth? He has the genes, just never hit the growing spree yet, what should he do, if he wants to stay in shape, but does not have the money to hire a trainer :(
would the workouts stated above stunt his growth or have a possiblity of stunting his growth?

[Renee Radenberg]

Cardio-vascular exercises (running, biking, stepping) are good to do and will build up muscle without issues.