More than likely they're closet jerks. They are on their best behavior when they're around other girls so they're not perceived as being jerks. In the absence of feminine moderation, their testosterone kicks in and they end up amplifying each other's dormant jerkness.
If it's something that he recognizes, then he at least knows it's not a desired behavior. You need to make a habit of reminding him to cool his testicles down after he hangs out with them. Then re-remind him any time he starts acting like a jerk afterwards.
Maybe you can comment to him about this transformation prior to his going to hang out with his friends and maybe he can work to moderate their discussions.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.