When he's been in there long enough to get bored of the bible and actually start checking out the prison library could be interesting if he writes to people enough we can keep track of it.
He might drop every book 2 chapters in but it would still be more interesting than a cartoon or game character.
If the prison allows people to send him books (some let you order books of your choice too I guess, maybe that would be enough motivation to work inside) I wonder if he could just get videogame and cartoon shit though.
He's not stuck with just the bible or nothing, but I don't know if he realizes that yet or just isn't bored enough and believes he'll be back to his videogames soon.