re: 14 year old weight training advice?

Never sacrifice stability for mobility. If he can not control his own body through a range of movement patterns, it wouldn't be wise to throw an external load on him. You have the right idea with starting him off with body weight exercises first. See how he responds to those. Of his mechanics are all over the place, than he needs to stick with body weight until he can control his own body in space. From there, I would probably look around using bands to provide an external load before throwing weights on him. Progressive isn't linear, so it may take some time for him to adapt. He may adapt quicker on certain exercises than others. I would also challenge him with a lot of core and balance and stability exercises. Teach him how to do a proper plank and have him do a crap ton of them. Also, see if he can do simple task such as just standing on one leg without any compensations.

Diet will do 50x for him what supplements will do. Keep protein high, plenty of non-sugar carbs and try to focus on healthy fats.

If he is very motivated, there are great mass gain programs like the vertical diet mentioned. He is at an age where there's a little dietary flexibility as long as he is getting adequate protein, calories and carbs.

I agree with D1. They’ll concentrate on form, and sport specific training. Safety first, then once form is down weight will come.

Y’all have al been so great easing the mind of a well meaning father. Hopefully last question for a while. I’ve told him no to protein powder, that he needs to eat more meat, beans, vegetables and simple carbs. With that being said, is chocolate milk a good recovery/protein drink that would be beneficial after workouts. By they way, I had to drag him kicking and screaming to his first session. Now, a week plus in and he’s made when he’s a couple minutes late. Thanks again for all of the advice.