Ways out
"Why did he help the police?"
They offered him something the cartel could not. Which at a guess would be freedom, albeit in hiding, rather than early retirement.
Maybe getting him and his family somewhere safe, so they can live out their lives in an extremely boring fashion. Like Rincewind, once life has shown you just how interesting it can be, sometimes being bored is the best thing possible.
I would also guess that he was targeted by the cops, since turning a tech-for-hire is probably easier (and more palatable to a jury) than someone on the more "conventional" cartel management ladder. He probably was more in fear of the cartel than feeling like he was a part of it. So it's entirely possible that the cops let him make his own demands.
I would expect that the Butcher's lawyers will at least make some allusions as to what the chap has been given, so the details of his deal might even make it into open court.
Biting the hand that feeds IT
