In the first episode of The Punisher (TV series), we see Frank living as isolated as possible while also working. He ends up overhearing about a planned robbery from his coworkers. Also, the coworkers end up roping the new, younger employee into helping them in the robbery. The robbery goes sideways when the kid accidentally reveals who he is to the mob and his coworkers decide to kill him. Frank at this point intercedes, kill the coworkers, and saves the kid, giving him the money. Frank then goes on and kills the mob that would have chased after the kid.
At this point, I'm confused as to why Frank gets involved. Why did he save the kid? The kid was just as guilty as the other people in the robbery, save for their attempted murder. What made him different enough to be worth protecting?