Boys are not like girls. You know that. Specifically, my boys don't share their feelings like girls might, although Three and Five come close, but with more violent imagery. My boys don't scream and cry at eachother, they just belittle and threaten. In short, they are dicks.
This is most apparent in the interaction between Two and Three. Years ago, they were thick as thieves. Two years apart in age, they were Frick and Frack, Donald and Goofy, Chandler and Joey. We have photographic proof. The age difference didn't matter when they were 11 and 9, but it is huge now that they are 15 and 13. Two is a good kid, but he can be ever so slightly superior and dismissive in tone, especially with Three. And he is absolutely not above calling him names, or pointing out his physical failings.
I think Three would like to still be friends with Two, but has been pushed away often enough that he's now just plain angry. This leads to seething, and descriptions of murder ("I'm going to lie in my bed and wait until he's asleep, and then I'm going to slit his throat. Just like that."). Then I get pissed off, drag in Two to make him apologize, punch Three when he flips him the bird, listen to them jaw about who said what, until I lose my mind and tell them to grow the fuck up.
Stunned silence. "Nice mouth, Mom."
Then I go watch Four and Five playing together on their bed. For now.