"He doesn't want to see the family business left in the hands of someone ... he feels isn't up to the job."
And the contempt Hancock had for Ginia was born of worry about who would be "assuming real and great responsibility of taking over the family company", Bianca Rinehart said.
She and Hancock have since reconciled, with Hancock backing her bid to take charge of the family's A$5 billion ($5.4 billion) trust.
Ginia was not the only one who angered her older brother.
Bianca, Gina Rinehart's eldest daughter, said her younger sister Hope Welker "was pretty much at her wits' end" and felt "kicked in the stomach" after the way she was treated by Hancock.
"All I feel is pain and anxiety. You are kicking me in the stomach," Hope emailed her brother in February 2013, Bianca Rinehart told the court.
Welker has withdrawn from the debate, distressed at the way it was proceeding, and dealing with her own divorce.
Hancock and Bianca Rinehart allege their mother acted "deceitfully" in her dealings with the trust, set up in 1988 by her father, Lang Hancock, with her children as the beneficiaries.
So far, every proposal for a replacement trustee - including Bianca Rinehart, Hancock and independent trustees - has been rejected during lengthy court proceedings.
- AAP