Hollywood star Martin Sheen has described his troubled son Charlie's struggle with addiction as a disease "as dangerous as cancer".
In an interview for today's Desert Island Discs, he said the actor's ongoing battles with his demons amounted to a "rollercoaster ride".
Charlie's career has been in meltdown in recent weeks, with his increasingly erratic behaviour and rambling public appearances turning into a global soap opera. He was axed from his lucrative role in hit TV show Two And A Half Men last month as things came to a head.
In the interview being broadcast on BBC Radio 4, Sheen Senior said it was something his family had to confront each day.
"Charlie is dealing with the most profound problems and addiction - there's no secret, his behaviour has been an example of that," he said.
"So if he had cancer, how would we deal with him? Well, he has another disease and it's equally as dangerous as cancer. And so we lift him up, we pray for him and be present (for) him and try to lead him as much as we can.
"But he's an adult and he needs a lot of help on a lot of different levels," added the former West Wing star.
The 70-year-old, whose film roles have included Apocalypse Now and Badlands, continued: "You know, he's been out there on his own for a very long time and as a family, you know, well, you never get used to it.
"It's a rollercoaster ride that's been going on for some time. So we deal with it, every day."
Sheen Senior has had his own battles with drink and has been a member of Alcoholics Anonymous since the mid-1980s, turning his life around as he embraced Catholicism.
He also tells presenter Kirsty Young about the heart attack he suffered in his late 30s while filming Francis Ford Coppola's Apocalypse Now in the Philippines in 1977.
He explains how he had to actively bring himself back as he drifted towards death for the sake of his children and wife Janet.
"I thought it was the end, I thought 'This is what it is like to die'. And I remember specifically thinking 'Well, it's not so bad' because at that point the pain had stopped and I was resigned to it and there was no fear.
"I remember that very, very specifically - and I remembered going, moving and then I realised that if I continued I would not get back. And I had to very specifically stop this journey and get back because I had too much responsibility.
"I had children and Janet, and it would be too much of a burden. So I began to literally will and bring myself back.
"I remember reaching out and pulling the grass and eating the grass - anything that would ground me, anything that would connect me, determined to stay alive.
"And the more that I got back into living, consciousness, the worse the pain became again."