The Made In Chelsea stars elder brother Michael died in 1999 aged just 22 whilst climbing the world's highest mountain, and the family were unable to bury him as his body was never recovered.
Matthews journeyed to Everest earlier this year on an expedition to make a film Finding Michael for Disney+ UK.
He said on his Big Fish podcast: "It was important for me to get my head around the fact I might come face to face with my brother’s frozen body.
"I knew it was going to be a gut-wrenching and emotional journey."
Matthews, 34, admitted he has only recent processed the death of his brother.
He said: "I never really processed Mike's death until just now. He died 23 years ago. He was 22, the youngest Brit to reach the summit, and I was 10.
"Losing him was not something I full understood, I just assumed Mike was my superhero figure in my life I assumed he would come back, I didn't believe he was dead for a period of time.
"As time passed I understood I would never see him again I've always had this burning desire to find him and understood how complicated that would be."
Matthews said: "I'm not a particularly externally emotional person. I cant really remember the last time I cried."
But he added: "It was certainly one of the greatest experiences of my life."
The reality TV star said his wife Vogue Williams was very supportive of his decision to journey to Base Camp in Nepal for five weeks when their son Otto was just five days old.
He said: "I had nothing but support from Vogue. [She] was so on board with it and so proud we were doing it. She feels really close to Michael, having neve met him of course."
The couple married in 2018 and are parents to four-year-old son Theodore, two-year-old daughter Gigi and seven-month-old son Otto.
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