This will be the fourth time John Michael McDermott, from Moorlough Road, Donagh, Lisnaskea, will be before the Crown Court to be sentenced either for the indecent assault or gross indecency of his victim.
McDonagh, who will be 63 this weekend, is one of four brothers originally accused of sexually abusing children in Donagh over a period of 50 years.
On Wednesday at Dungannon courthouse, McDermott, the only brother to be jailed for their "tidal wave of abuse", pleaded guilty to two further charges of sex abuse on a schoolboy on differing dates between August 1989 and September 1990.
However, as in his last appearence before the court, Judge Jeffrey Miller QC has already indicated it is unlikely that the custodial sentence he imposes next month will have any material effect on the sentence he is currently serving.
McDermott was originally jailed for nine years, along with three years on probation, in June 2010, then given an additional six months in October 2011, and six weeks in September last year.
Judge Miller pointed out on Wednesday that McDermott's latest crimes had already come to light when he was last before the courts, and if dealt with then, it was unlikely, given the principle of totality of sentence, that he would have received a more severe sentence.
However, Judge Miller, who ordered an impact report on McDermott's latest victim from prosecutor Suzanne Gallagher, said a final determination of his sentence will only be made next month.
Ms Gallagher said she would be making submissions on sentencing when McDermott is next before the court.
It had been expected on Wednesday that defence QC Martin Rodgers, would have applied for the case against McDermott to be "stayed", however, he sought to have him re-arraigned before the court, at which point McDermott pleaded guilty.
Originally two other brothers, James McDermott, 62, and Owen McDermott, 54, were charged with offences relating to the sexual abuse of youngsters in the Donagh area during the 1970s and 1980s.
However, they were deemed unfit to stand trial because of their mental disability.
While a jury found that they had carried out the abuse, there was public outcry when they were given a two-year Supervision and Treatment Order allowing them to return to the family home beside a children's playground.
They have since moved to secure accommodation within a psychiatric hospital in Londonderry.
A fourth brother, Peter Paul McDermott, 62, died by suicide the day after he went on trial for his role in the abuse - abuse which Judge David McFarland originally said had turned what was "a quiet picturesque village in County Fermanagh ... into ... a village that had an appalling secret, and it was the children who bore the brunt of the tidal wave of abuse".
Judge McFarland said the "deviant" McDermott brothers had between them "stolen" the childhood of their victims, subjecting them to "horrific" abuse, although "some, of course suffered more than others, some for longer period, and some were abused by one or more brothers".
However, when coming to deal with McDermott in October 2011, Judge McFarland said the "sentence of six months is appropriate. On its own, I acknowledge, it is a lenient sentence.
"But when taken together with all the offences, it means a commensurate sentence of twelve and a half years, a sentence I believe correctly reflects your offending."
McDermott's original sentence of nine-year jail, plus three years probation, followed his guilty pleas to a total of 35 offences, involving the abuse of four boys and a girl, including the rape of a schoolboy, committed between 1969 and 2001.