Kidnap victim Kevin Michael McGeever faced the barrel of a gun in captivity and told his captors he was ready to die.
His brother Brendan said the developer (58) -- who was held for eight months -- told his captors he had "made his peace with God".
"He was given written notes and they would say, 'You have two more days to live.' They put a gun to his forehead one time and he said, 'Alright, do it now. I have made my peace with my God. I am ready.'
"That happened quite a few times, it wasn't just the once."
Meanwhile, the garda investigation into the reported abduction is a work in progress, according to Commissioner Martin Callinan. He said it was "early days".
They are currently examining information given to them by Mr McGeever and others about the eight-month period for which he was missing.
Brendan McGeever told the 'John Murray Show' on RTE Radio 1 that he became concerned about Kevin after his brother had sent two texts to his partner, Siobhan O'Callaghan.
One was supposed to have originated in the UK and the other in Germany.
"They (the texts) were saying, 'I am sorry I had to leave, I'll make it up to you when I get back'," said Brendan.
Kevin McGeever was reported as missing by his partner at the garda station in Gort, Co Galway last June -- several weeks after he had been taken from the garden of his home in Craughwell by armed and masked men, according to the account that he later gave to gardai.
Brendan said he didn't know what kind of projects his brother was involved in.
"I knew he was involved in Dubai and this sort of thing. He would be talking about Dubai and he would be talking about Abu Dhabi. He would say that was the place now coming up and that sort of thing."
Asked if he was aware whether his brother was in financial trouble, Brendan said: "He wasn't happy about it but there wasn't a lot he could do.
"Dubai itself was in economic collapse big-time. He was concerned about all that."
Yesterday, the Irish Independent reported that Kevin was held by police in Dubai five years ago during an investigation into his property dealings. Clients had complained that their money had gone missing.
Kevin was discovered in a dishevelled condition on a country road near Ballinamore, Co Leitrim, last week.
Brendan said his brother had turned from a 14-stone man into a man who looked like "a weather-beaten 90-year-old that's just been released from a concentration camp".
He said his brother had been interviewed by gardai investigating his disappearance.
"What he said about where he had been I wouldn't want to tell over the air," said Brendan. "But he was held somewhere in Ireland.
"When he realised he was being dropped off he was thrown into the back of a van.
"He was dumped on the side of a road in Ballinamore. He didn't know where he was. They gave him a telephone with one number on it. When he pressed to operate this number, no signal came up.
"He was trying to walk and he couldn't. He somehow scrambled on to the road and a car came along. A lady took him into Ballinamore. They went to the police station and they gave him a cup of tea.
"He didn't say anything about his captors. We didn't go into that."
Brendan said Kevin did wonder where some papers reported that he may have been held on behalf of the Russian Mafia.
"He did say in the hospital that this was nonsense."
Kevin claimed that his captors never spoke and only communicated via writing and gave him very little food.
Brendan said he had no idea why his brother was abducted and held for so long. He couldn't say if any money had changed hands.
He added: "I have no reason to disbelieve my brother. He is not going to tell lies to me."