Aslan singer Christy Dignam nearly died on the operating table when his heart stopped twice during a lengthy operation.
The 'Crazy World' singer, who has been diagnosed with leukaemia, had to be revived twice by medics during a six-hour operation last week.
Towards the end of the operation, surgeons inserted a pacemaker in order to stabilise his heartbeat.
An insider revealed how doctors now fear that cancer-stricken Christy, 52, could possibly have further complications to some vital organs and he has been undergoing a series of tests to establish how much the cancer has affected his body.
According to his Aslan bandmate Billy McGuinness, Christy has been drug-free for many years. He spent two decades fighting a debilitating heroin problem, even visiting the renowned Wat Tham Krabok clinic, which is run by Buddhist monks, in Thailand in 2004.
The singer had recently given up cigarettes and told friends he couldn't believe how he got sick just as he was beginning to look after himself.
And Billy revealed how everybody from Gay Byrne to ex-Westlife performer Nicky Byrne had sent best wishes to the singer.
But the guitar player was annoyed by a nasty post on Facebook last Friday, which claimed that Christy had died.
Billy said: "I don't know why somebody would do that. It's so awful. But we all nipped it in the bud. Over 10,000 fans have sent best wishes to him on Facebook, which is just incredible. Everyone is behind him. I've been speaking to him on the phone. He sounds tired, but he's still in great spirits.
"He's still in Beaumont and they say he's already started responding to treatment.
"He was apparently in a ward full of oul' fellas due to a bed shortage, but I think he's been moved now. I've told him how he managed to fight heroin, so he can definitely beat this."
He added: "He's very positive about it all. I haven't been able to get in to see him because of the influenza outbreak in Beaumont, but I will."
Christy's wife Kathryn, who was his childhood sweetheart, called an ambulance when the singer became short of breath while at home early last week.
He was taken to Blanchardstown Hospital where doctors confirmed that a chest infection had turned into pneumonia. But he was later diagnosed as having cancer and underwent treatment immediately.
After spells in the Blanchardstown and Mater hospitals, Christy is now in Beaumont Hospital, where he is not allowed any visitors.
After his admission, Kathryn and the couple's daughter Kiera issued a shock statement on Facebook revealing that Christy had cancer and that all Aslan gigs had been postponed.
They had been due to play a special St Patrick's night gig in the Olympia Theatre this evening. Now Billy, also 52, and the band have given Christy a goal to aim for in his recovery.
He said: "We're supposed to play our new single 'Catch My Fall' on the Saturday Night Show on RTE on April 20. Christy is aiming to be back in action to do that. We recorded it with songwriter Don Mescal and all proceeds are for Pieta House, the organisation dedicated to suicide awareness.
"We're completely confident that Christy will be back in action by then. He's a real fighter. He's going to make it."
Christy also has another goal in mind – to attend daughter Kiera's wedding to her fiance Darren this June.
Kiera, 26, who featured as a baby on the sleeve of one of Aslan's early albums, is also a singer. She auditioned for The Voice of Ireland earlier this year, but failed to make it through to the next round.