WARNING: The following contains spoilers for The Next Batman: Second Son #4, from John Ridley, Mark Morales, John Livesay, Travel Foreman, Deron Bennett and Rex Lokus, on sale now.
In Future State, the journey of how Tim "Jace" Fox became the new Dark Knight was kept a mystery. He wasn't chosen by Bruce Wayne, and the former billionaire didn't have anything to do with this passing of the baton; Jace basically stole the mantle for himself after Bruce was assumed dead. In fact, even Nightwing was left clueless as to how Jace turned into Gotham's new Caped Crusader.
But in The Next Batman: Second Son #4, we see the history of Jace prior to him donning the cape and cowl, and his new job at his father's company hints at how he could have gotten access to his arsenal.
This story kicked off with Jace in Vietnam, hunting terrorists down after fleeing Gotham for an unseen past sin. Despite his past, Lucius loves his son and wanted him home, especially after the "Joker War" almost left him dead. Grifter was hired and pulled Jace out of the mission, but since being back with the family, Jace is at odds as he doesn't like how his dad covered up their rocky past.
However, Jace gets a massive and most welcomed distraction when his handler, Vol, reveals that his target from Vietnam, the shady arms dealer Arkadine, is in town making a trade. Jace tracks the villain to a Gotham airstrip but realizes he can't attack the arrival since he's so outnumbered. To make matters worse, Arkadine has upped his hacking defenses since Jace broke in digitally last time to steal data.
Knowing Arkadine has reinforced, Jace decides to make a big move of his own to get new tech, and he officially takes a job at his family company as the issue closes. Since he always wanted Jace in the family business, Lucius is glad, but he doesn't realize that he's mainly there to steal research, parts, tech and whatever else he needs to go after his enemy.
Now, given that Lucius has come up with so many weapons, vehicles and a huge portion of Batman's arsenal, it's not hard to imagine Jace discovering the schematics and that he needs to allow him to become the new Batman.
This adds a layer of irony to Jace's Batman because his dad thinks his dad hasn't given him anything in life except a standing of money and privilege. While it's not clear if or when Lucius will learn about his son's status as the Next Batman, he still built a foundation for Jace to become Batman on both a moral level and a technological one.