Is Dick a Preacher?

The only thing I really noticed was the phrase preaching dick. So I'm imagining that he's at least well at speaking but probably literate too. This is a preacher. He likely had literacy skills, right? He might have even been able to write though he doesn't talk about that. But this man is using his religious ability, right? Or at least Robert Grace believes he might use it in order to continue to run away.