I mean, if he actually were convicted, executed, and later proved innocent…

That is one of the few circumstances that an official “Saint Luigi” could literally happen. Despite the memes, it is an understatement to say that it is extremely unlikely that the Catholic church would ever beatify someone for shooting someone else in the back with a silenced pistol. But to be falsely convicted and executed for the crime? That would make Luigi a completely innocent martyr for the cause of the sick and injured. That’s the stuff sainthood is made of.