The Tiflin family is a close-knit one in that they know or care for little else other than each other. Life on the Tiflin ranch is, for the most part, a quiet, peaceful one. But make no mistake, Carl Tiflin is the man of the house and it is his lead that everyone is supposed to follow.
Billy Buck is like the fifth Beatle. He's not actually a Tiflin, and has no family ties to them. But truthfully, Billy is as much a part of the family as any of them. They treat him like one of the crowd. And he seems to feel the same way about them.
We get a much better look at Jody as a person than anyone else in the book and that is simply because it is his coming-of-age story that Steinbeck focuses on. He is an impressionable youth who is affected by just about everything that happens on the ranch. For example, when the old Mexican Gitano leaves, Jody feels it right down to his bones:
A longing caressed him, and it was so sharp that he wanted to cry to get it out of his breast. He lay down in the green grass near the round tub at the brush line. He covered his eyes with his crossed arms and lay there a long time, and he was full of a nameless sorrow. (2.173)
This little moment (and others like it) tells us a lot about what kind of kid we're dealing with. He's a thinker, and a dreamer, and he wants, badly, to explore those mountains. He's got a sense of adventure, but he's also kind of a homebody. No wonder he feels so torn up.
Let's talk about Billy for a minute.
From day one, we can tell Billy's an expert because he's handy on the ranch. His actions make that undeniable. He cares for the animals and the land with ease.
But Billy's human, just like anyone else, and his mistakes tell us just as much about him as do his other actions. When he misreads the weather and the pony pays the price, Billy does everything he can to rectify the situation.
And later, when the colt's in jeopardy, Billy does what he has to (as horrifying as it may be) to save the colt for Jody. Sure, Billy's not perfect, but he gets the job done, come rain or come shine.