Let him skip breakfast. As long as his metabolism is in good working order, he’ll be fine.
For lunch, I don’t really know what you could pack that wouldn’t look odd to friends. You can still stick with a piece of fruit, but other than that you’ll want to get in some protein, and fats. Maybe some nuts, or pack in some cheese (if you do dairy, that is). If he’s really keen on the whole pizza flavor thing, you could make meatza, and pack that along, but that would be messy, cold (unless he can heat up his lunch), and maybe a little weird. I guess in short tell him to tell his friends to quit being such tools.
I’m a particular fan of Stronglifts, mainly because it’s a good place to learn about building strength for beginners, and it covers a lot of from – the main thing starting out is to make sure you’re lifting with proper form.
Branched chain amino acids (BCAAs) would be one hell of an expensive way to get him aminos. Usually BCAA’s are used during a workout to supply energy to muscles. You might try a casein protein isolate (might not give an acne response), or an beef protein isolate. I’d suggest him just eating 50g (at a minimum) protein and 100g carbs (sweet potatoes) for post workout.
If you're having trouble convincing him to stick to paleo, you could tell him that in order to gain muscle, and do well in sports, etc., he needs to be different than everyone else. If he wants something, (being bigger than all the other kids), than he has to do things to get it done, and he can't expect something for nothing.
