Holland is the youngest of three siblings and as the only lawyer, was a co-trustee of her father's estate.
When he died in 2001 she was nominated attorney under her mother's enduring power of attorney for property and personal care.
Holland's mother died in September 2013 and she was aware that she and her two siblings were the executors, trustees and equal beneficiaries under her mother's will.
Despite taking control of estate matters, her mother's will was never given to the Tribunal during the hearing. Her brother - an overseas-based medical specialist - had never seen it.
Holland filed documents suggesting a variety of defences, including a denial that a lawyer could be liable for conduct outside the provision of regulated services; the allegations were a family issue, it was inappropriate for Law Society intervention; and that she owed no fiduciary duties to her siblings.
However, when before the Tribunal she changed her stance and said her brother had told her he did not expect to receive any share in his father's estate, that her brother had stolen a significant part of her records, and that her conduct fell short of the threshold.
But the Tribunal's deputy chairperson, Judge John Adams, didn't buy her account, stating the allegation of theft by her brother was a "convenient construction".
"The allegation was belatedly made. It is so desperate as to seem unhinged. It strengthens our sense that Ms Holland is unreliable and perhaps has something to hide in the non-provision of records."
He said it emerged through her evidence that she was "aggrieved by the fact that her brother is comfortably situated, whereas she has had an increasingly hard time".
Holland was in "particular financial need" in 2009, and noticing $53,000 had accumulated in her mother's account, took it as what a Law Society indicated was a loan to herself from her mother's estate.
Her family home was sold by mortgagee sale in 2011, before she was bankrupt in 2017.
Judge Adams said the Tribunal accepted Holland took a greater share caring for her mother than either of her siblings, including her overseas-based brother and that expenses could be claimed.
"Unanswerably, Ms Holland helped herself to much more than she was entitled, even if such matters were taken into account."
He noted Holland failed to produce any adequate records to help find what distributions had been made.
"We can see the deposit of just over $300,000 into her then employer's trust account in January 2002 but the trail ends there.
"The fact that we are unable to cobble together any sort of reliable record thereafter tells
the story.
"We accept that some funds have been advanced to her sister, but we do not know, and are unprepared to accept her word, as to how much."
The tribunal found they could only speculate as to how much she had advanced herself- between $200,000 and $285,000.
"And that range is uncertain if we note that we are unsure what total amount actually passed beneficially to her sister."
Despite being in a position of trust, Judge Adams said even when giving evidence before the Tribunal, she "failed to recognise the extent to which she had imperilled her mother's position and hampered her brother's ability to obtain his residuary share, falls short of the care one would expect in a lawyer, even though not acting as a lawyer providing regulated services".
Surmising Holland's case, Judge Adams wrote, "over a period of many years, she ignored clear fiduciary duties, promoted her own interests and, when called to account, she has been avoidant, obstructive, and plainly irrational".
"This is our firm, unanimous view."
A half-day hearing would now be set down to assess an appropriate penalty.
The Tribunal suppressed the names of Holland's family.
