Just to add some general gym etiquette, if your son isn't already aware:
* Never do curls in the squat rack!
* Don't hog equipment. If you're doing something that requires a lot of different weights in succession, for example, either use your own weights or try to attend when the gym is less busy. Don't be that guy who insists on having the entire dumbbell rack to himself
* Don't drop weights, even in the free weights area - it's antisocial and dangerous, and makes a very distracting noise. While there are odd times where you will HAVE to drop the bar/dumbbells for safety, if you are regularly finding yourself having to drop weights, you should either consult a personal trainer or find a gym with Olympic lifting facilities (i.e. a massive, thick mat on the floor)
* Similarly, if you find that you're regularly slamming the weight down while using machines, you're doing it wrong. The machines should not be making that much noise.
* Re: wiping down equipment, the gym may provide wipes for this, but IMO it's better to bring your own towel to save waste.
Finally, on a non-etiquette note, good on you for encouraging your son to exercise! It might be good to invest in one session with a personal trainer for your son just to make sure he's using good form.
Thank you for your encouraging post! He's your typical 13-year-old football player in a championship-team high school: he's girding his loins and prepping his mind to FIGHT! FIGHT! FIGHT! for the team when he gets to it in two years.
He made a loud noise today when he was on one of those bicep-/tricep- machines today. I think he "slammed" something.