It was really no surprise to Mike Kaelin when his brother Bill was announced as the winner of a Nobel Prize last week.

Dr. William G. Kaelin Jr., of Harvard University, Dr. Gregg L. Semenza, of Johns Hopkins University, and Peter J. Ratcliffe, at the Francis Crick Institute in Britain, were named the winners of the 2019 Nobel Prize for Physiology or Medicine. They were recognized for discovering how the body senses and adapts to changes in oxygen.

Discussing his accomplishments, Mike and his wife Carol Kaelin paint a picture of a man who not only possesses great intelligence and mental acuity, but one who puts his family and friends first, and exhibits humility and social grace.

Bill and Mike Kaelin were two of five children, four boys and one girl.

“We grew up together and we’ve been together ever since,” Mike Kaelin said in an interview with Hearst Connecticut Media. “We went to the same high school, college and professional school.”

They attended Roger Ludlowe High School in Fairfield, Duke University, and Duke University Medical School for Bill and Duke Law School for Mike. They went to the same college because their father wished all his children to go to Duke.

“Notwithstanding how brilliant he is academically, intellectually, scientifically, even though I went to the same schools he did, there is no way you can make a comparison between him and me, especially in math and science,” Mike Kaelin said. “No one really compared to him.”

When Bill was a freshman at Duke, he was the top student in math and chemistry, Mike Kaelin said.

“It’s impossible to exaggerate how smart he is, but notwithstanding that, he is such a down-to-earth regular person,” Kaelin said. “He is gifted intellectually, but he has friends.”

As an example, Kaelin said when his brother celebrated his 60th birthday and the 20th anniversary of his lab at the Dana-Farber Cancer Institute two years ago, hundreds of the post-doctoral fellows he had hired over the years came back from all over the world to celebrate with him.

“Once you become a friend of his, you become a friend for life,” Kaelin said.

Building on his everyman image, Carol Kaelin said, “He’s extremely articulate for a scientist. He can explain things so the average person can understand.”

In an interview with the Associated Press, Dr. Kaelin explained aspects of his work.

“What we discovered is a molecular pathway or molecular network that all multi-cellular organisms use … to allow cells and tissues to know if they’re getting enough oxygen and to respond accordingly,” he said, comparing it to a thermostat.

“There are many diseases that are characterized by inadequate oxygen delivery, such as anemia or heart attack, stroke or for that matter many solid tumors. So one thing this has enabled us to do is, with the circuit in hand, develop drugs that will either activate or inactivate this particular molecular circuit,” he said.

In addition, that pathway is co-opted by “certain cancers and in those cancers we’d like to be able to turn the pathway off,” he said.

The reason the Kaelins were not surprised to hear Bill won the Nobel Prize is that he’s been honored with a number of prestigious awards, including the 2016 Lasker Award for medical science by the Albert and Mary Lasker Foundation. The Lasker is America’s most prestigious biomedical award.

One key difference between his brother and other scientists, Mike Kaelin said, is that Bill was a practicing physician. He studied internal medicine and became an oncologist.

“He’s actually cared for patients, including his wife Carolyn, who died of cancer in 2015. What’s different is a lot of people who have labs like he has and have made the discoveries he makes, they have Ph.D.s, not MDs,” Kaelin said.

“What’s different about Bill and really beneficial to the work he’s doing, he has such a better feel for the application. He’s not just doing things in a laboratory or test tube. He knows from first-hand experience what he’s doing in the lab will affect a patient’s care and make a difference in their lives,” he said.

The Kaelins attributed some of Bill’s success to the relationship he had with Carolyn, who was a gifted breast cancer surgeon at Brigham and Women’s Hospital. She survived breast cancer only to later be diagnosed with a brain tumor that claimed her life.

“Carolyn really pushed him hard,” Kaelin said. “Whenever he would think he’d reached a limit on something, she said, ‘never say that.’”

The Kaelins had dinner with Bill on Saturday and said, “The only thing that’s changed is so many more people are trying to talk with him now.” A pre-planned lecture that took place two days after the announcement was standing-room only and had a line for selfies.

The Kaelins have another date with Bill. The Nobel awards ceremony is Dec. 10, and they’ve got their plane tickets to Stockholm.