Leaving the mafis isn’t exactly that easy; you’re bound by the crimes that you’ve committed, and the crimes you know your fellow members committed. You’ll never be free, unless your entire Familia collapses or gets busted.
Actually, that does give me an idea. How about, this LI tries to get out while the Familia is at the break of collapse? At first, he tries to stay and preserve what he’s lived with, but getting to know the MC makes him realize that he should pursue a more modest, law-abiding life? Of course in the manner of a slow burn.
There’s absolutely cases of former mafia men living such lives today that went through exactly this, after all.