Sad Secret Phil Donahue Took to Grave: TV Trailblazer Spent Decades Battling to Save Son Dan From Twin Horror of Drug Abuse and Mental Illness

Legendary TV host Phil Donahue waged a heartbreaking battle to rescue his son from the twin demons of mental illness and drug abuse for years before his death this past weekend at the age of 88.

RadarOnline.com can reveal Donahue's first wife, Marge Cooney, broke her silence to reveal Dan, the third of the couple's five kids, suffered from schizoaffective disorder and addiction – and Donahue did "everything he could to help" his tormented son for decades before his passing on Sunday.

Cooney said before her ex-husband's death: "Phil has done everything he can to help Dan. He's been a loving and wonderful father."

Dan Donahue was said to be in and out of treatment centers for more than half his life while his loving father quietly picked up the staggering medical bills – which at times totaled up to $500,000 a year.

And even though the couple's marriage didn't work out, Donahue and Cooney remained united in their love and prayers for Dan up until their deaths.

During her interview in 2002, Cooney added Donahue's second wife – Marlo Thomas , now 86 – was "incredibly supportive" of the talk show icon's efforts to provide his son Dan with whatever he needed.

Cooney said at the time: "Dan's had the best treatment money can buy, as well as all the love and support his family could possibly give. But it still wasn't enough."

In addition to schizoaffective disorder, a mental illness that runs in families, Dan also suffered from brain damage sustained in an auto accident 55 years ago.

Schizoaffective disorder causes patients to experience crushing depression and schizophrenia at the same time – often accompanied by hallucinations and delusions.

The disease makes it almost impossible for a patient to think clearly, manage emotions, make decisions and relate to others.

Cooney, 22 years before Donahue's death on Sunday, said: "With Dan's illness, stimuli come to the brain as a barrage. It overloads the circuits, and you turn to alcohol or drugs to medicate yourself."

But she added Dan's long history of cocaine, marijuana and alcohol abuse only made his treatment more difficult.

In 2002, Donahue and Cooney's troubled son lived in a cottage on the grounds of the famed Silver Hill Hospital in New Canaan, Connecticut, where celebrities like Tatum O'Neal , Darrell Hammond and Billy Joel previously sought treatment for their own addictions.

The anguished mom said she lost count of how many times her son had entered rehab.

But her generous ex – who earned $20million a year in the 1990s and later signed a short-lived million-dollar deal to debut a new show on MSNBC in 2002 – never balked at footing the bill for Dan's treatment.

Dan was just 14 when his parents divorced in 1975 after 17 years of marriage. Like his brothers Michael, Kevin and Jim, he lived with his father in Chicago while his sister, Mary Rose, moved to New Mexico to live with his mother.

Then, in 1977, Donahue fell in love with Thomas after she appeared on his hit daytime talkshow program The Phil Donahue Show .

Donahue, years before his passing, said his and Thomas' May 22, 1980 marriage brought love and order into his son's hectic and drug-fueled life.

He said at the time: "There was a great rapport. When we would have dinner, I would learn more about our kids from listening to them talk to Marlo than when they were talking to me."

But when Dan was 18, tragedy struck. A severe head injury he suffered in a car crash seemed to have kick-started his psychosis.

Cooney said in 2002: "You have this bright, intelligent, engaging 18-year-old who never showed any signs of mental illness. Then – over a period of months after his accident – he mysteriously starts to change behavior."

Decades later, the family remained shattered by Dan's illness – but Donahue knew at the time of his death he did everything possible to help not just his son Dan but also his and Cooney's four other children.

He said years before his passing at 88 on Sunday after a long illness: "I think my epitaph should read: 'There lies Phil. He done his damnedest.' I think the kids would agree."

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