It was a simple cheek swab that saved a New Brunswick father and his son nearly 20 years apart.

David Boudreau and his son Samuel, 21, have each received a bone marrow transplant.

​At just a year and half, Samuel was diagnosed with Fanconi anemia, a disease that mainly affects the bone marrow and decreases the production of blood cells.

"Eventually, his bone marrow would've failed," said David, who felt an overwhelming feeling of shock when he heard the news in a hospital room.

Over time, Samuel got sicker and was in desperate need of bone marrow.

After a few tests, doctors discovered his older brother, Sylvain, who was three at the time, was the perfect match. Typically, siblings have a one in four chance of a match, said David.

Sylvain, now 22, doesn't remember much of the surgery except the large bandage on his back.

Every doctor would explain the bone marrow and I said, 'We don't have to, we already went through this with our son.' -David Boudreau , cancer survivor

It was 1998 when the family headed to the Hospital for Sick Children in Toronto for Samuel's major surgery.

"It was a good day," said Samuel, who now works at a pharmacy in his hometown of Bouctouche.

"Now I'm feeling well."

David said he couldn't have been prouder of his eldest son as doctors got to work.

"They went in like 20 times with a needle … when he got out he was pretty wiped," said the 51-year-old.

As a reward, he asked for toy cars and trucks.

"I was promising the world when he woke up."

Samuel, right, received bone marrow from his brother, Sylvain, who is 16 months older. (Submitted by David Boudreau)

But after the surgery that saved his life, the uphill battle continued for Samuel, who was in and out of hospital for the next seven years.

"They almost had a mug on there with our names on it, we were there so much," he said of the hospital stays.

Nightmare continues

The Boudreau family had no idea they'd be in for more twists and turns years down the road.

It was a typical morning in 2010, and David was in the bathroom shaving when he noticed a lump underneath his jaw.

David, then 44 years old and active in hockey and karate, decided to visit a doctor just in case.

After several tests, doctors relayed the news that he had non-Hodgkin's lymphoma, a cancer that starts in white blood cells, part of the body's immune system.

For years, he had different treatments, but nothing worked. His last shot at survival: a bone marrow transplant.

The Boudreau family at Christmas last year, from left to right, Veronique Boudreau, David Boudreau, Carole Boudreau, Samuel Boudreau and Sylvain Boudreau. (David Boudreau)

"Every doctor would explain the bone marrow, and I said, 'We don't have to, we already went through this with our son,' " he said.

"It's a big thing for one family to go through a bone marrow [transplant] but two is insane."

After his name went on the registry list, the father of three knew he only had a 50 per cent chance of getting a match.

He waited for a month and a half, calling several times for updates — hoping for good news.

You don't know who it is. You don't know who you're helping. -Cory Sandstra , bone marrow donor

Finally, he got word of a match, and the bone marrow transplant was done in Halifax in March 2016.

A donor in Edmonton saved his life.

"I knew it was life or death," David said. "Either I find a match or I was done."

A year after the surgery, David reached out to the mystery donor he now knows as Cory Sandstra.

"At first it took me half an hour pacing in the house," said David, who is still recovering from the surgery.

"I told him, 'I'm not sure if I should call you brother, angel or both.' He said, 'Cory will do.' "

Getting the call

When he received David's phone call, Sandstra described the conversation as overwhelming and emotional.

"The more I've been able to get to know who David is and the stuff his family has been through, it made it worth every minute of what I did," said Sandstra, trying to hold back tears.

Sandstra was in Grade 11 when he decided to donate his bone marrow. He was encouraged by a classmate to add his name to the registry.

Nearly 20 years later, his marrow matched a patient in need.

"You don't know what to expect — that's the unique thing of an unrelated donation," said the 35-year-old, whose grandmother's sister also died from leukemia.

"You don't know who it is. You don't know who you're helping. "

For the past few months, the newfound friends have been communicating through text messaging. They're hoping to meet in person someday, talk about hockey and their mutual love for the Montreal Canadiens.

"He saved my life," David said.

A need for donors

In the meantime, both David and Samuel Boudreau want to draw attention to the need for more bone marrow donors.

"We need more names on the registry," David said. "Sometimes that's the only way to get cured."

The cancer survivor is encouraging people to visit onematch.ca and sign up. A kit with instructions will arrive in the mail. If there's a match, donors will be contacted, and it could take years.

"One day it could happen to your family," David said. "With us it saved two lives."