Why do your posts always show up so late lol?
As I wrote above, this is bodyweight dependant.
First, I want to make it clear that I think he should join a gym for optimal growth.
For external loading, he can fill a backpack with weights. This can be used for push ups and chin ups.
Again, this is not about the exercise, but the amount of resistance. If he's below 155lbs, pull ups won't do much either without external loading.