Alex Ferguson was treated in hospital last Saturday after suffering a nosebleed which, according a close friend of the United manager, left him in "tremendous pain".
"I was in Munich when we heard about the 999 call for Ferguson," revealed American broadcaster Charlie Stillitano, a long-term friend who is due to interview Ferguson on Sirius XM's The Football Show, this week.
"I was worried for the first couple of days, until I spoke to him. He was in tremendous pain. He basically had a nosebleed which wouldn't stop and he was in pain. It can't be pleasant when you're 70 years old and you are bleeding uncontrollably -- thoughts must enter everyone's head.
"But I have been speaking to him every day and he has been getting better. He sounded terrific when I spoke to him on Friday."
The incident prompted Whelan to claim on Friday that, "after next season, Alex will call it a day because he had a little scare".
However, Stillitano insisted that the Scot reiterated his determination to continue at Old Trafford during a conversation following Whelan's comments.
"He [Ferguson] was laughing when I spoke to him on Friday and I said, 'Are you going to retire?' and he said, 'No, nothing has changed'. He is going to continue until it is his time to step down.
"If you keep doing your profession at the top, you stay sharp and that is what Alex is thinking. He doesn't want to step down.
"Dave Whelan's comments are reasonable. He knows Alex and everyone realises that, at 70, you have to start thinking about retirement, but maybe not [in Ferguson's case].