They shouldn't be scared at all. Goku will just somehow give the Roaring Knight a nearly unlimited boost only because he wants him as strong as possible to "fight" him, then he'll fucking die by having a heart attack or something. Just don't ever let Gohan enter the Dark World and you'll be fine
"Kris, this can't just be a me and you thing. It needs to be... Goku's thing, too." #Deltarune