Why was "her" used here?
In accordance with studylight.org:
"...brother, in a boot makynge nettis. 20 And anoon he clepide hem; and thei leften Zebedee, her fadir, in the boot with hiryd seruauntis, and thei suweden hym. And thei entriden"
I think, that "their" should be used instead.