The High Court has ordered a couple, who received almost €300,000 from their friend and claimed that the money was a gift, to repay the money immediately, with interest.
The money was part of a sum of €750,000 given to Ms Kerrigan, from Ballyshannon in Co Donegal, as compensation for injuries she suffered in a road accident in which her father died.
The court heard the Keenaghans paid off all their debts, financed their children's education, retrained as counsellors and psychotherapists, and opened a new business.
They claimed the money was a gift given to them "out of the blue" when they were in financial difficulties.
Ms Kerrigan, meanwhile, is now in very poor financial circumstances and is living on payments from the Department of Social Protection.
Today, she said she was "glad it was all over" but was "deeply disappointed" that her friends had betrayed her.
Ms Justice Deirdre Murphy said the Keenaghans had chosen to deny their debt, instead of acknowledging it, and this was an enormous breach of trust.
This morning, she ruled the Keenaghans must pay interest on the money, at a rate of 8% set under legislation, beginning from 2014, when Ms Kerrigan originally asked Mrs Keenaghan to begin repaying the money.
The judge set out a schedule of how interest should be applied from 2014 to the date of her judgment. She said this reflected what should have happened.
The judge awarded the costs of the eight-day hearing against the Keenaghans, despite a plea for "some little mercy" from their barrister Desmond Murphy, to award just six days' costs.
Ms Justice Murphy said the court had urged the parties to resolve the matter before the court came to a decision, but that did not happen.
She said the whole event came before the court because of Ms Keenaghan's breach of trust and "costs must follow the event".
This means the losing party must pay the costs. The judge refused to postpone making her final orders pending a possible appeal by the Keenaghans.
Mr Murphy said they had not decided yet whether or not to appeal.
He said he accepted he would be facing an uphill battle trying to convince an appeal court that the judge had made an error in deciding on the facts, but there was still a possibility he could succeed.
Lawyers for Ms Kerrigan said she had given the loan in 2010 and had asked for it back in 2014, and now four-and-a-half years later, she was still waiting for her money.
They said she was living in very poor financial circumstances, dependent on social protection payments and there was no reason her difficulties should be unnecessarily continued.
Ms Justice Murphy said the court should not prolong the agony any longer.
She said the Keenaghans had not advanced any credible legal argument as to why a stay should be granted and she refused to postpone making her final orders.
Ms Kerrigan's solicitor, Damien Tansey, said the Keenaghans had succeeded in transferring their financial problems to Ms Kerrigan's shoulders.
Her situation was dreadful, he said, and she was utterly dependent on social welfare.
Mr Tansey said the judge had highlighted the fact that the Keenaghans had significant valuable property assets.
If they did not pay the amount of the judgment, he said they would register a charge against those assets and sell them out, in order to ensure there was a fund available to repay the money to Ms Kerrigan.
He said she needed it for the remainder of her life.