Not to worry, we've got this noted on the app page!

"Exceptions can be made for characters that absolutely need something to survive, like built-in cybertech, life-force crystals, or a reactor that keeps shrapnel from cutting into their important organs. Items like this may be similarly "capped" so that they can't be used as weapons or tools within the fleet."

So he can keep his sword... And you can decide whether you want it to be locked up, turned into something less harmful, or just capped into being harmless towards his fellow passengers.