So the entire playbook thing is relative in a way. You don't have to learn all 300-700 pages in one go. When you install week to week, you will have to learn it then, and than get to rep it. I am sure players go over and read it, but you can always learn it and master it when it's installed against that particular opponent.
I'd expect his brother to get promoted soon. I even wonder, if Judd Garrett gets moved up. Move John to OC, and Judd as a TE coach. Now you add another brother into the fold.