en_tn/2ch/21/04.md

risen up over his father's kingdom

To "rise up over" something is an idiom that means to control it. Alternate translation: "taken complete control over his father's kingdom" (See: rc://en/ta/man/jit/figs-idiom)

he killed all his brothers with the sword

Jehoram probably did not kill them personally, but had other people do it for him. Alternate translation: "he caused all of his younger brothers to be killed" (See: rc://en/ta/man/jit/figs-metonymy)