(May 11) - More than 10 years ago, Brian Monaghan was diagnosed with stage 4 melanoma that spread to his brain. Doctors gave him six months to live, but he's still alive today. He credits his wife, Gerri, for his survival and said on Good Morning America that she was his biggest advocate for beating his cancer.

"There are other things that may have helped me make it, but I would be dead it were not for what she did," Brian, a former trial lawyer, said in the interview, which was broadcast Monday.

Immediately after her husband was diagnosed with cancer, Gerri made a list of how to fight the illness and put it into a folder called "To the War." That list and subsequent writings were the basis for the couple's new book, 'The Power of Two: Surviving Serious Illness with an Attitude and an Advocate.'

In it, the Monaghans lay out 50 tips on how to survive a serious illness with the help of an advocate.

"You're on emotional overload when you're the patient. And I think the most vital thing an advocate can do is be there (in a doctor's office), bring a notebook with you, write it down and make doctors speak to you in a language you understand," Gerri said.

Watch the Monaghans' interview on Good Morning America.