Real talk: the narrative technique of our story is kind of weird. For the whole novel, we're inside Billy's head, hearing what he's thinking and feeling what he's feeling. Often, that means we're dealing with a first-person narrator. Billy is definitely the one telling the story here…but he never says "I."
Here's a good example:
Billy wishes Crack would just smack the fool and be done with it, but his fellow Bravo merely stares the guy down. Perhaps one melee is enough for this Thanksgiving Day. Billy checks his cell. Nothing from Faison. Yet. He indulges in another episode of the ranch fantasy, but now while he and Faison are having sex ten times a day he's also thinking about Bravo back at FOB Viper, getting slammed every time they go outside the wire. So he puts that inside the fantasy, how much he'd miss his fellow Bravos, he would mourn them even as they live and breathe. They are his boys, his brothers. Bravos would die for one another. They are the truest friends he will ever have, and he'd expire from grief and guilt at not being there with them. (Proud.60)
Because we're so close to Billy and his thoughts all the time, we almost get the sense that he's talking about himself in the third person, as if he were just a bit on the cray side. We almost feel like voyeurs, watching all of Billy's thoughts as he dissects them for us.