It started with a little heartburn, in the fall of 2016. Oak Bluffs businessman Tony daRosa didn’t think much about it. It wasn’t bothersome enough to make him postpone a golf trip to South Carolina with his friends.

But when he returned to the Island that fall, he thought he had better get the heartburn checked out. His doctor ordered some blood tests, which he did one morning at the Martha’s Vineyard Hospital.

“Came back to work,” Mr. daRosa said. “They called me and said they wanted me to come back to do the labs again, they wanted to check something. From there they threw me in an ambulance and took me to Tufts.”

At Tufts Medical Center in Boston, doctors soon confirmed that Mr. daRosa’s kidneys were failing. They helped him establish the grueling routine of dialysis three times a week, and began to talk to him about a transplant.

Kidney issues began in fall of 2016. — Ray Ewing

The best solution for a kidney transplant is usually to find a live donor willing to give up one of their own kidneys. The body systems of most people operate just fine with only one functioning kidney.

Mr. daRosa turned to family and friends for donor candidates. He found plenty of support.

“We all went up, there was seven of us that wanted to test,” said Mr. daRosa. “That made me feel pretty good.”

It turned out Mr. daRosa was pretty lucky. His daughter Erin was a good match. But after she went in for more extensive testing, doctors decided against using her as a donor.

It turned out Mr. daRosa was even luckier than he thought. Doctors turned to the second donor candidate they found after preliminary testing, a very statistically unlikely candidate, Erin’s husband Mike DeBettencourt. He was a perfect match. The medical staff at Tufts told them they had never seen a donor match between a father in law and a son in law.

Tufts medical team said they had never encountered a match between a father in law and son in law. — Ray Ewing

As the scheduled Dec. 12 surgeries neared, Mr. daRosa had the slightest of second thoughts.

“My numbers were going in the right direction, doing the dialysis,” said Mr. daRosa. “You have that thought of, maybe this isn’t necessary. But then they [the numbers] jump around, and I knew there was no way my kidneys were coming back.”

For Mr. DeBettencourt, who owns DeBettencourt’s Garage in Oak Bluffs, there was never a doubt.

“I was happy that I could help him and it was just a natural thing for me to do,” said Mr. DeBettencourt. “He’s my father in law, grandfather to my children, and father of my wife. To be honest with you, I didn’t think it was that big of a deal. I said, why not. I talked to all the people at Tufts. I was going to do it, no matter what, but they ease your mind even more. They tell you the statistics, they tell you it’s nothing more than a C-section. It was natural, I thought.”

Both men were released from the hospital after just a few days of recovery from the operation. By early January, both were back at their jobs feeling normal, with the exception of occasional fatigue at the end of the day.

Neither man is all that emotional about the life saving surgery. They speak in a humble, matter of fact tone about something many consider a medical miracle.

Mr. DeBettencourt said the only thing that makes him feel slightly uncomfortable is the number of people who shake his hand and call him a hero.

“I don’t consider it a heroic act,” said Mr. DeBettencourt. “I just consider it something that’s natural. My father in law needs a kidney, I’ll give him a kidney.”

Mr. daRosa’s reaction was both matter-of-fact, and heartfelt.

“Thank you, Mike,” he said.