A fit and healthy young football coach died from deep vein thrombosis after spending hours during the coronavirus lockdown playing computer games.
Centre Parcs worker Louis O’Neill, 24, was furloughed in March and took to gaming with friends to while away the boredom.
His grieving father Stanley Greening, 56, warned other families of the dangers of youngsters being cooped up in their bedrooms without being active.
On social media Mr Greening wrote: “On 3rd June something so awful happened, the worst imaginable thing to happen to such a young man and the worst imaginable thing to happen to a parent. My son, my dear Louis, has gone.
“Not from the evil virus, but because of it. His young life, barely begun still trying to find his feet, just torn away. The devastation… after seeing my dear boy go like that I am in a living hell.
“This damn lockdown. After being furloughed he took to his gaming world to escape. Caught up in a virtual world he became less active, so easily done.
“Hours fly by when absorbed by the screen. I have done it countless times myself. But no-one I mean no, ever in a million years would have predicted a blood clot. And just like that, it ripped my son away and I died inside along with him.
“24-years-old. Who is warning youngsters? Who is warning anyone of any age? No one. So I am. My son will live on, I shall continue to spread this warning in his name.“
Mr Greening, from Harlington, Beds, said: “This terrible thing was preventable had he or we known such risks.
“Like many I associate it with older people and something we are warned about on planes.
“As more and more of us are working from home it is likely you are not getting out of your chair as much as you needs. Stand up, walk around and please warn your kids.
“If I can prevent one loss in my son’s name then that’s one bright light that will shine on Louis. So Stand up for Louis.”
Louis’ funeral was on June 24, and the family have sent up a memory giving page for a youth sports charity.
In an interview with BBC Three Counties Radio, Stanley, who works as an artist, said: “He was furloughed within a week of the lockdown. He was quite jolly and said: ‘I am going to enjoy a bit of this.‘
“Louis has always enjoyed his games. He was chatting to his friends and I think he found some comfort in that. He had his friends on line. He had a virtual world to exist in during the nightmare that was going on outside.
“Hours would go by. I couldn’t say how long he was on the computer. There were times when I would get up in the morning and go down stairs for breakfast and he would be up and I would would realise he had been up all night.
“6-7 hours at a time, probably with very little break. He was sitting there all day. He put on a little bit of weight on.
“I was encouraging him to come out with his little sister. He would say yes. He came out a couple of times to the shops, but it sort of fizzled out and he got a bit down.
“I couldn’t make a 24-year-old go out. I was nagging him and he was getting upset with me. He was saying leave me alone.“
Two weeks before Louis died his father said he got up one morning at half past five and saw Louis sitting on a step near the bathroom. He said: “Dad can you help me? I have not been feeling well.”
Stanley said: “I helped him upstairs. He was approaching his bed, his weight was falling. I caught him and put him on the bed and he passed out.
“I shook him again and he woke up again. I rang 111. They got a doctor to call back and the doctor suggested that it had been food poisoning.”
Stanley and his son managed one walk to his allotment, but after that Louis said he was tired and said his leg was bothering him.
At half past ten at night on June 3, Stanley said his wife found Louis bent double at the top of the stairs. He went on: “I helped him into the bedroom and thought ‘It is happening again.’ l called 111 straight away.
“He sat on the floor against the bed and said: “Dad’s what happening to me?”
Paramedics arrived, but he died.
Mr Greening added: “This was so preventable. That’s what hurts. These are hidden victims during the lockdown.
“I remember my son saying to me, Boris Johnson said we are going to lose some loved ones. He said that is terrible. “