Former chairman of Dunnes Stores, Mr Ben Dunne, said last night his cocaine addiction would have killed him if his sister, Ms Margaret Heffernan, had not sacked him from the family company.
Speaking on The Dunphy Show on TV3, Mr Dunne said: "People talk about Margaret and myself, but one of the great favours Margaret done me was firing me from Dunnes because there were three in our family at the time who was addicted and two of them are dead.
"I believe if I hadn't been fired from Dunnes, I really believe heart and soul that I would have gone the same route. I couldn't have taken all that pressure."
Mr Dunne, who now owns a chain of gyms, spoke to Eamon Dunphy about his arrest for cocaine possession in Florida in May 1992 and his subequent battle with cocaine addiction.
Mr Dunne was caught by Florida police attempting to fly off a 17th floor hotel balcony, having spent the night with a call girl.
"It takes a long time to destroy yourself and the unfortunate thing - the road back - it takes just as long to get back," Mr Dunne told Mr Dunphy.
"I was a sick man using cocaine. It was having a grave effect on me... What I should have done, and saved everybody a lot of pain, was dealt with my personal problems."
Mr Dunne said he used cocaine at home after the Florida incident and "got a panic attack and jumped off the wall and cracked my heels into my ankles and was in a wheelchair for 16 weeks.
"From there I then had to pick the pieces up. I was gone from Dunnes... Then you get some lucky breaks and you go down the right road and you persist and persist and persist and you get there.
Mr Dunne also spoke about his friendship with former Taoiseach, Mr Charles Haughey, to whom he gave over a million pounds.
"I felt there was a reason for doing it, a charitable reason. I was asked by somebody to do something for Haughey and I did it. If that's a crime, I'm guilty.
Mr Dunne said he "got on very well" with Mr Haughey.
"Even at this stage today I say 'There go I but for the grace of God'. I think Haughey, though, has done an awful lot of good things for this country."