When Edwin and Pamela died in 2014 and 2015, respectively, they granted probate of their estates to Graham in their wills - something that had previously been discussed among the whole family.
"The evidence at trial established that Graham worked long hours on Kingsborough, that he took minimal drawings, and that it is likely that the farm would have had to have been
sold if Graham had not left school to work on it," the Court of Appeal's decision said.
Jillian and her sister Rachel - an "unwilling but necessary" participant in the court proceedings - had not shown an interest in working on the farm, which their parents had wanted to keep in the family.
"It was their intention from at least 1999, and probably earlier, that Graham, as the only child who had shown any interest in farming Kingsborough, should receive the family farm, and that Rachel and Jillian should share equally in the remainder of their estates."
The couple left Jillian and Rachel over $1m each with Jillian also being given the family bach.
The Court of Appeal said the key issue for it to determine was whether or not adequate provision had been made from the estate to meet Jillian's needs.
During the trial, it was established that Jillian already had significant personal assets and income earning potential.
Her partner was independently wealthy and, in cross-examination, she had acknowledged she and her family did have a comfortable lifestyle.
The Court of Appeal agreed with the previous decision that it was hard to see how an inheritance of just over $1m was insufficient to adequately provide for her.
"In our judgment, a sum a little in excess of $1 million is, on any objective assessment, and at the least, a moderate amount. It is not provision so small as to leave a justifiable sense of exclusion from participation in the family estate," the decision said.
"We consider that Jillian has not been excluded from the family, and that appropriate recognition has been given to her as a dutiful and loving daughter."
Jillian was ordered to pay Graham and Rachel's court costs for the failed appeal.