Richard Brennan was jailed for eight years in July last year after pleading guilty to raping and indecently assaulting two of his sisters when they were children and indecently assaulting a third sister.
Paula Fay said afterwards that she and her sisters Catherine Wrightstone and Yvonne Crist were extremely disappointed with the original sentence, and the DPP had appealed it on the grounds of undue leniency.
Brennan pleaded guilty to 24 counts against the three sisters during his trial after each of the women had given evidence and two of them had been cross examined.
He was aged between 16 and 24 at the time of the offences.
Ms Fay was aged between 15 and 17. Ms Wrightstone was between nine and 13 while Ms Crist was assaulted when she was 18 and Brennan was 20.
The abuse was committed in the family home in Rathfarnham in Dublin.
Brennan, who is now 65, was ordained a priest in 1989 and moved to the US. He later married and had a family.
During the trial, the court heard that he told Ms Fay, when she was 14 or 15 years old, that she would be doing him a favour by having sex with him as he would not be able to have sex with any girl when he became a priest.
Mr Justice David Keane sentenced him to nine years with the final 12 months suspended.
Giving the Appeal Court’s ruling, Ms Justice Isobel Kennedy said Brennan’s offending was of an "extremely grave nature".
She said it involved multiple aggravating factors including repeated rape, exploitation of vulnerable children, a profound breach of familial trust and devastating consequences for each victim.
She said the impact on all three sisters was "severe and long lasting".
Ms Justice Kennedy held that the discount for mitigation to the global headline sentence was "excessive in all circumstances" and the suspension of one year was "unjustified".
She said too much weight was given to mitigating factors including a very late plea of guilty, followed by a letter of remorse.
She said, overall, the sentence imposed failed to reflect the gravity of the offending.
The sentencing hearing had been told that Brennan grew up in a somewhat chaotic and violent family home.
His defence counsel John Byrne said Brennan had been naturalised into deviant sexual behaviour by his older brother Bernard.
Bernard Brennan was jailed earlier in 2025, for four and a half years for 11 counts of indecently assaulting Ms Fay and Ms Crist between 1972 and 1975 beginning when they were aged seven and 13.
In a statement outside court, Ms Fay said she welcomed the Court of Appeal's decision to substantially increase the sentence. She described it as a "profound moment of justice and vindication".
Ms Fay said historical sexual abuse left deep scars. She said the original sentence felt like a second injustice and failed to reflect the devastating lifelong impact of the abuse inflicted on her. But she said, the Court of Appeal had put that right.
Ms Fay said the court had sent an unequivocal message - that a late plea of guilty did not erase a campaign of abuse and did not diminish the trauma inflicted on victims who had to endure the gruelling process of giving evidence and cross examination.
She said she felt an overwhelming sense of relief that the gravity of the case had finally been recognised.
Her sister Catherine Wrightstone said justice had been served. Ms Wrightstone said she had spoken out aged 12 and had not been believed. And she said it meant a great deal to finally hear that acknowledged.
Ms Wrightstone paid tribute in her statement to Lavinia Kerwick, who spoke out in 1992 after the man who raped her was allowed to walk free from court and eventually received a suspended sentence. Her case led to the start of a process to allow victim impact statements to be heard in court and to a change in the law to allow the DPP to appeal the leniency of sentences.
She also paid tribute to other women who were raped and waived their anonymity to speak publicly. She said these women, including Hazel Behan, Paula Doyle, Sarah Grace, Bláthnaid Raleigh, Ciara Mangan and NGOs such as the Dublin Rape Crisis Centre had been fighting for years to reform laws for survivors. But she said little progress seemed to have occurred.
Ms Wrightstone said she had written to the Minister for Justice in April, outlining eight specific changes she would like to see happen to improve matters for survivors. But she said while her email had been acknowledged she had not received a substantive response and had not been granted a meeting.
She said she and her sisters had not waived their anonymity for sympathy but so change could occur. And she said she wished those in positions of power would actually listen to survivors and take action towards meaningful change.
She urged other survivors to reach out to organisations such as the Rape Crisis Centre as she said there were "gentle hands and open hearts who will believe you and help you heal".