John admitted he had concerns that Tyson wasn’t ready to fight after his daughter was rushed to intensive care just weeks out from the fight.
After drawing the curtain on his three-fight series with The Bronze Bomber, Tyson Fury returned home to Morecombe earlier this week to be reunited with the rest of his family.
Fury, who remarkably picked himself up off the canvas twice, ended the trilogy with an 11 round knockout against Wilder, bringing a conclusion to their long-running discord.
But his father, John Fury, has unveiled that his son put his preparations on hold to stay by his newborn daughter Athena’s side at the Alder Hey Children’s Hospital and could see the pressure it had on his son.
Speaking to Sky Sports News, John Fury said: “I went to Alder Hey Hospital, I accompanied him just to keep him right. I said, 'look, you've got to do some form of exercise, just don't sit in here. Let's go for a bit of a run, you'll feel better after it.'
"I'm 56 years old, 20 stone, I outran him. We went for a run round Liverpool and his lungs were on fire, I thought 'look at this'. My lungs? You couldn't hear them. He struggled with a three-mile run.
"He said afterwards 'that nearly killed me' so that's where he was at four weeks prior to that big night."
Fury, who had to postpone the fight, which was scheduled to take place in July after contracting Covid-19, resumed training once Athena was discharged from hospital, but his father admitted that he had concerns over his son’s fitness.
“Deep down inside I was worried because I thought 'you know what, he shouldn't be doing this.'
"There's a power to be in boxing, Tyson wanting to stand up for his country knowing Anthony Joshua just lost his belts at home, two miles from where he lives.
"He thought: 'You know what, I can't be like this man, I've got to do my own thing, stand for my country. Win, lose or draw it's on!'"
But in what will go down as a fight for the ages, The Gypsy King’s fitness shone through as the boxer battled his way through to the eleventh round outlasting Wilder to retain his heavyweight title.
With his eyes now on a fight against Oleksandr Usyk to unify the heavyweight championship belts, his father John has told fans to appreciate his son’s brilliance while he’s still at the top of his game.
John said: "I can only commend my son, there'll never be another man like Tyson Fury ever in the sport of boxing.
"I told him: 'You're that good, it's scary!'
"He's the full package, he's proven everything, there's nothing more for him to prove. If he walked away today he's done his business, won every professional title there is to win.
"He's a remarkable human being, so embrace him while he's here because when he's gone, he's gone, and then you're back to the boring stuff - the losing.
“The belts will be gone because - let me tell you something - it'll be a long time before those heavyweight belts are held here again because I think once they leave these shores when Tyson's gone they're staying gone."