I'm not sure how to put this? If other inmates ask you to do something that is illegal or you do not want to do. How would you say no without pissing other inmates off?

This is a slippery slope for sure... He needs to separate himself from this group if he is hanging with inmates who are still looking to break laws even while incarcerated. But if he's running with this crowd, he's gonna be guilty by association even if he declines. If he's truly serious, he really needs to do whatever he can, including seeking a transfer, to not be in a position where additional charges get tacked onto his sentence.