Helen Watson, whose son Peter was abused while Ryan was working as a priest in Ararat, said she was dumbfounded when she left the sentencing hearing earlier this week.

Now aged 70, Ryan was sentenced to 26 months' imprisonment at the County Court of Victoria, after pleading guilty to three charges involving the sexual abuse of children.

After dispensation for his guilty plea and time served, it means he could be entitled to apply for parole in just 13 months' time.

Mrs Watson, who now lives in Beaufort, said she supported one of the three victims through the trial process.

Her own son Peter was abused while staying overnight at the Ararat presbytery in 1991. Ryan was never tried for the crime as Peter took his own life eight years later.

"I couldn't speak when I left the courtroom," Mrs Watson told The Courier. "I couldn't understand how such a sentence could be handed down."

"He will be a free man by Christmas 2020."

She said the victim she was supporting was also devastated. "Ryan.... has ruined countless lives including destroying our beautiful son," she said. "The victims have a life sentence, Ryan gets a slap on the wrist."

One victim said he had never let anyone get close to him as a result of the abuse.

His victim impact statement was summed up in the judge's sentencing remarks: "His guard was always high and he was scared to be himself in case he was hurt. He had never been able to allow himself the joy of companionship, as he had 'too many walls up' to have feelings.

"His friendships were few and far between as he could not let people get close to him for fear they may know the full extent of the secret of your offending or his pain. [The victim] did not want anyone to know about that, even his parents."

Another had battled depression, and said the abuse took away his innocence.

Previously, Mrs Watson has described how her "kind, gentle" boy had been affected by the abuse, which he kept secret for many years. He went missing in 1999, but his death was not confirmed for more than five years.

I cannot fathom how a legal system can support the plea of the abuser while the victims are dragged through court, in this case for three years.

Helen Watson

In fact, Ryan went to jail in 2006 only a few months after Mrs Watson finally learned of her son's death. He was convicted of three child sexual abuse charges. He was released a little over a year later. Mrs Watson, who gave evidence to the Victorian parliamentary inquiry into child sexual abuse in 2012, stressed that her disappointment was not directed at Judge Susan Pullen.

She said Judge Pullen had done what she could within the confines of sentencing guidelines. In sentencing remarks, the judge described Ryan's crimes as "most serious and disturbing" and an "abuse of trust and power."

"Your offending, moral culpability and personal responsibility was high," she told the court.

Mrs Watson reserved her sharpest criticism for guidelines linking prison time to the sentencing lengths recommended at the time of the crime. She queried how Ryan had managed to reduce his sentence by pleading guilty, and accused the former priest of manipulating the system.

Reading a pre-prepared statement, she said: "I felt shattered beyond belief."

"I cannot fathom how a legal system can support the plea of the abuser while the victims are dragged through court, in this case for three years.

"Something needs to change so that the perpetrators are not given so many dispensations. Guilty is guilty."

She urged government and the legal profession to work together to strengthen the sentences for those convicted of historical child sexual abuse.

The victims of your offending have suffered enormously and long-lasting adverse effects

Judge Susan Pullen

Ryan was ordained in 1976, and went on to work in Warrnambool, Hamilton and Ararat. Two of the victims were at St Joseph's Christian Brothers College in Warrnambool. One was 15 years old when he was abused in 1981; the other was 17 when Ryan assaulted him in 1985.

READ MORE: Helen Watson's relentless quest for justice for her son Peter

A later Ararat-based victim was 14 and an altar boy when Ryan abused him in 1992. Ryan was only defrocked in 1993.

"The victims of your offending have suffered enormously and long-lasting adverse effects," Judge Pullen said.

Despite her disappointment at the sentence, Mrs Watson says the victims do not have any intention to appeal against its leniency. Instead, she is pinning her hopes for justice on more people coming forward.

"He's a serial paedophile," she said. "I know there are more victims."