Depends a little on his height, weight, bodyfat, activity (in the gym and outside of it), and his goal, but generally, no, a 16-year old kids don't "need to" track macros specifically. Eating smart every day and training hard a few days a week will go a long way.
I suggest the basic guidelines I laid out in the whole last section of this article. Not avoiding animal protein, good carbs, or healthy fats; 3 or 4 meals every day; learn to cook the basics.
A little junk food is definitely no big deal once in a while. It could easily be argued that trying to have him eat only clean foods can be a bigger issue than the occasional pepperoni pizza.