His 30-year career as a solicitor disintegrated before his eyes, his wife and children left him and many he once called friend now want nothing to do with him.

Sitting in the witness box in Wollongong District Court on Friday, Duncan summed it up in just a few words: "my life is nothing. I'm just existing".

It's been almost two years since one of Duncan's client's phoned his employer, Maguire and McInerney to complain about him not returning their calls in a case.

A review of the file by one of the partners uncovered a $7262 payment that had come from another deceased estate and not from the correct estate.

Maguire and McInerney reimbursed the money to the correct estate had Duncan pay back the same amount and brought in a team of forensic accountants.

What they unearthed was staggering in terms of its size and scope. Duncan had carried out a sophisticated fraud scheme, worth $2.1 million, right under the noses of his employers.

He misappropriated almost $758,000 from deceased estates, using the cash for home improvements, car leases, and to pay for his mother's nursing home bills - a matter Duncan's three siblings claim only came about because their brother stole from their mother's estate for 10 years before her death in 2015 (see below).

The remaining funds - some $1.39 million - were made up of fraudulent financial transactions Duncan made to cover his tracks.

Maguire and McInerney acted swiftly, firing Duncan, notifying affected parties and taking out a loan to repay their clients in full.

Then they turned on Duncan himself, launching civil action in the NSW Supreme Court to force the sale of the family home to recoup costs.

Meanwhile, Duncan was arrested in December 2018 and charged with two counts of fraud, to which he pleaded guilty. He remained on bail after his arrest, making a meagre living working as a truck driver in Dubbo.

He told the court he couldn't describe how low he felt: "I have virtually got nothing. I'm just existing."

But if Duncan thought he'd hit rock bottom already, he was in for a nasty surprise in court on Friday: he was going to jail.

In sentencing Duncan to a minimum two years' jail, Judge Andrew Haesler was at a loss to find any explanation for his behaviour.

"Yes, he was in debt, but to risk everything.....it beggars belief why he did what he did," he said.

"He knew the obligations to himself, his his family and his clients and he breached those over a long period of time."

Duncan will be released from custody on October 2021 then be subject to parole for another 21 months.

Wollongong solicitor Nigel Duncan may have been abandoned by most people in his life since he was outed for committing mass fraud against clients, but he did have three surprise supporters in court for his sentencing hearing on Friday - siblings Fred, Fiona and Mary Duncan.

They, more than most, know what it is like to be a victim of their brother's deceit.

The trio, who grew up in Wollongong but now live in Tasmania and flew up to attend the court proceedings, claim Duncan fleeced hundreds of thousands of dollars from their mother while she was still alive, leaving her virtually penniless at the time of her death and in debt to the nursing home where she spent her last years.

"That's why he used the money [from the deceased estates] to pay her debts, because he'd taken all her money before then - in excess of $420,000," Fiona said.

The siblings said they feel a deep sense of betrayal at their brother's actions.

"We knew nothing about Nigel's thefts until they were exposed two year's ago," Fred said.

"We're absolutely disgusted with what's happened.

"We had no cause not to trust him - we have been betrayed."

However, all three have chosen not to abandon their brother and even housed him in Tasmania after his arrest.

The siblings said they were brought up in a loving, close-knit family with strong, community values instilled in them by their solicitor father Fred.

"Our parents were well respected in Wollongong - Nigel betrayed their values," Fred said.

"We don't know how his [Nigel's] values got so screwed up to be honest."

The trio said they attended the court proceedings in part to support their brother, but also to make sure the truth was revealed and to "give their parents a voice".

"Mum's dead but she's not at peace. We came to defend mum and dad's memory."