HALIFAX — Phil O'Hara and Brad Crossley may not be biological siblings, but there's no denying they're family.
"My children think about his children as cousins and vice versa," said O'Hara. "His children call me Uncle Phil, my children call him Uncle Brad."
O'Hara and Crossley have been best friends for more than 40 years, all thanks to the Big Brothers, Big Sisters program.
"Phil was my phys-ed teacher in Grade 5 and at that point in life, probably until I was 14 years old, I lived in 11 different apartments and went to eight different public schools and had a great supportive Mom that did everything she could to keep me grounded and on track and then Phil came along as a big brother," said Crossley.
Over the years the duo have travelled together and even stood in each other's weddings.
"Our relationship isn't one-sided. Brad's been my mentor through the last number of years in an unbelievable number of ways," said O'Hara.
"We've named our children after each other and have done adventures together and run businesses together and now this little challenge," added Crossley.
O'Hara, 68, is living with terminal cancer, a diagnosis he's taken in stride.
"The cancer I have is not curable and I've exhausted all my treatment options. So, I'm on a bit of an experimental drug that we'll know around Christmas time whether there's any effect but it won't be a cure, it will just extend my life a little bit," said O'Hara.
"You just don't know what's going to be dealt your way every day," said Crossley. "I have to tell you, the life he lives now, the passion he has for it, the love of life and the desire to live is just amazing."
A lifelong educator, O'Hara has been writing about his journey with cancer on his blog. It's a way to help other people who may not have the support system he does.
"I just felt that this was going to be the biggest teachable moment in my life," said O'Hara.
"I just thought that maybe I could help other people by chronicling my adventure with cancer right from the get-go. It's worked really well. It's far better received than I ever expected, and not just by people with life-threatening diseases."
This weekend, O'Hara will tackle his first Bluenose Marathon with his best friend by his side.
"The last time I ran, I did a 5k the week before I went in for surgery for my cancer and that was the last time I ran. I've lost so much weight, I can't run anymore," said O'Hara. "I'm pretty fragile, pretty weak, but not in spirit."

"Phil's going to walk the start and he's gonna walk the finish and I'll push him the rest of the way and we'll have a great time doing it and it'll be something that we'll remember forever," said Crossley.
Although some days he struggles to get out of bed, O'Hara said he's determined to live an exciting, full life.
"I didn't ask for cancer, cancer blindsided me. There's nothing I can do about that. But what I can do is choose to be the best person I can be on every day in spite of the cancer," he said.
This week, the pair are training for the marathon. Some of their friends and family plan to join them Sunday morning for the 10k race.
"I think when we cross that finish line, that will be one of those moments of absolute joy inside and nirvana that you just it will be like the guy who breaks the ribbon at the Boston Marathon," said O'Hara.
In addition to the upcoming marathon, the pair are looking forward to travelling to Boston together to visit Crossley's daughter, who lives there.
"We know the chances for us to have the kind of adventures we've had over the years are becoming limited. I have a shelf life. Don't know what it is exactly and with cancer you never know, but I'm living large and I've made the decision to live large so this kind of adventure with us doing this race is just an extension of that. I'm doing huge things in my life right now, putting check marks on bucket lists," said O'Hara.
To contribute to Phil O’Hara’s initiative to raise funds for Big Brothers, Big Sisters of Greater Halifax, you can click here.