Aubrey Smith was just 28 when he became a victim of Sudden Arrhythmia Death Syndrome - a failure of the heart in an apparently healthy person.
His girlfriend and his two brothers, Rod and Gavin, were waiting for him at the finish line, unaware that Aubrey had collapsed in a Glasgow street.
They eventually received a phone call from the emergency services telling them the terrible news.
Rod, 30, is one of a group of around 40 people running this weekend's Great Scottish Run to raise funds for the charity Cardiac Risk in the Young (CRY).
He said: "Gavin got the phone call and we were taken to a mobile police office and told what happened.
"We couldn't understand it, it didn't make any sense.
"We're raising funds for CRY and we also hope to raise awareness of what is a much more common thing than you might expect.
"The hope is to get more young people to get heart screening.
"The reality is it wouldn't have helped Aubrey as we still don't know what went wrong with his heart, but it might save other people.
"The idea is that we will all try to run as a group and finish in Aubrey's target time of two hours."
Aubrey, who was born in Canada but lived in Glasgow, worked at commercial property research firm CoStar in West Nile Street.
Of the 40 runners, 26 are current and former staff of the firm.
Martin Smith works at CoStar and knew Aubrey for around 18 months.
In that time they became close friends and Martin describes Aubrey as a funny, kind and memorable person.
Martin, 28, said: "Aubrey became such a good friend to me and our work colleague Jamie Campbell.
"He was the funniest guy I'd ever met and he could just floor you with a remark or one of his stories.
"He was into running and he was a very fit guy.
"I do remember him saying in the weeks before the half marathon that he hadn't trained as hard for this one and he felt a little like it might not be the best idea.
"I got the most horrendous phone call that night, but I can't even begin to imagine what it must have been like for his brother and girlfriend who were waiting for him at the finish line.
"The mark of the man is that he made an impression on everyone he met.
"He was memorable, and I don't ever recall him raising his voice or arguing with anyone.
"I know people say this about folk in these circumstances, but it is absolutely the case with Aubrey."
Martin and a host of CoStar colleagues will run either the 10k or the half marathon on Sunday and they are already more than halfway to their fundraising target of £10,000 for CRY.
Martin added: "I'd never ran more than about 5k before I started training for the half marathon.
"Quite a few of us are novices and there have been some injuries along the way.
"Aubrey would laugh at the thought of us all going through this, but we want to finish what he started that day."
Alison Cox, chief executive and founder of CRY, said: "It takes great courage and determination for anyone who has been affected by young sudden cardiac death to be able to see beyond their own situation and to want to raise funds for CRY and to help us increase awareness of our work, including screening, advice and support.
"On behalf of all of us at CRY, I would like to say a huge thank you to the huge number of runners who will be taking part in the Great Scottish Run, in memory of their friend Aubrey Smith who died so tragically last September aged just 28 and we wish them every luck in their fundraising event."
A website has been set up for anyone who would like to donate to the fundraising effort.
It can be found at www.justgiving.com/jamie-campbell8