Lunaris invaded Earth, throw it out of orbit, and worse, trying to destroy everything and everyone on Earth including his own. I say it was all because of Della handing Lunaris the rocket designs and Louie for disabling the defense satellites to accelerate the invasion.
Bradford could’ve used the event he saw to make Scrooge McDuck and his family feel extremely worse and to make the world turn against him. He even could’ve thrown Lunaris in the Solego Vortex first as a demonstration to F.O.W.L.’s enemies, and then he should’ve dump Louie in as well to spite Scrooge and keep him broken permanently.