Editor's note: Imagine being a father and finding out you were going to die. Who would be there for your kids? Hear from one man who thought only of his daughters when he was faced with the news. Watch "Dads for My Daughters," a special Dr. Sanjay Gupta documentary to air June 19 and 20 at 8 p.m. ET on CNN.
NEW YORK (CNN) -- Bruce Feiler remembers how he felt in May 2008. "I was a healthy person," and he was on the top of the world. Happily married, father to twin girls and a best-selling author. His book "Walking the Bible" was celebrated, and it gave him the nickname, "The Walking Guy." He made a living exploring the world, literally walking in other people's shoes.
But on that day in May, he was stopped in his tracks by a routine blood test. "My doctor says your alk phosphatase number is high," Feiler recalls. "She explains that alk phosphatase vaguely suggesting that there is something wrong with your liver or your bones. Another test, my liver is cleared and she says almost like on a whim, why don't you get a full-body bone scan?"
That test revealed a growth on his left femur, or thighbone. Feiler remembers his doctor was not concerned. "She says. It looks like nothing, don't worry, it's not like you have cancer. I repeated that a lot. 'Don't worry,' I say to my parents. 'Don't worry,' I say to my wife. 'Don't worry,' I say to myself. I don't have cancer."
But Feiler's wife, Linda, had a hunch that something was wrong: "You know as a wife, as a spouse. You know as a parent when something's just off. And he just didn't look himself. "
A follow-up X-ray and MRI of his left leg revealed an 8-inch cancerous tumor. The official diagnosis was an osteosarcoma. Osteosarcomas strike just 900 Americans a year. Two-thirds of them are younger than 40. Feiler was 43.
Read more: Dads for My Daughters
"It's uncommon to have this diagnosis," says Dr. John Healey, vice chair of the Department of Surgery at Memorial Sloan-Kettering Hospital. "I know it's not going to show my patient any mercy, and I'm not going to show it any mercy."
His colleague, medical oncologist Robert Maki, said Feiler's age was not in his favor. "The bulk of people who get osteogenesis sarcoma are below age 21. They seem to do less well overall. We don't know exactly why that is the case, what is the difference. They just don't respond as well for some reason. "
A father's 10 lessons for his daughters
News of the diagnosis terrified Feiler. "There's never a moment that is not shadowed in some way by that cancer, illness, the idea of dying is never that far away," he says.
The man who'd made a living by walking knew he might never walk again. He knew that he might not live to see his twin daughters, Eden and Tybee, grow up. "I'm a person who has tried in my life to dream undreamable dreams. Who's gonna teach them how to dream? Who's the person that's gonna tell them if they want to run a marathon, open a restaurant, write a book, cook the hardest soufflé. Who's gonna say to them, 'You can do it?'"
Feiler came up with a extraordinary answer. He would put together a group of men and call them his council of dads. Six men from different stages of Feiler's life who could be Feiler's voice, and could teach his girls the life lessons he might not be there to teach.
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Jeff Shumlin and Feiler met traveling the world. As comfortable on a tractor in Maine as on a train platform in Europe, Shumlin would teach the girls how to really know and learn the world around them. For Shumlin, even a mud puddle can make for an adventure,
"Go out and jump in the mud puddle," he would tell the girls. "Thrash around. Find out what it feels like and come out covered in mud. As long as you jump in, there will always be something to learn."
For childhood friend Ben Edwards, it was not about the mud puddles, but the tadpoles. They walked into kindergarten holding hands. And spent their afternoons trying to catch tadpoles in the neighborhood drainage ditch that they could grow into frogs. For Feiler, it became a metaphor. "He is my tadpole. He is that friend who was there at the beginning, who came back at a moment of possible ending to remind me where we came from."
Edwards would teach Feiler's girls about history, fun and friendship. "You just want your kids to have a base of where they're from," Edwards says, "And hopefully I can give them that base and they remember, you know, that this is tadpoles and frogs and just happy, happy times."
It would take four other men to capture the other facets of Feiler's personality, and of his voice. His college roommate. His business partner. A fellow writer. His closest confidant. These men would step in if the unthinkable happened. And, during Feiler's battle with cancer, they would fight alongside him.
Feiler would need an army. His yearlong roller-coaster fight for life bought him to the brink of death. Would he survive? And, would the council be there for his girls?
The story of that year is told in the Sanjay Gupta documentary "Dads for My Daughters."