Michael has always reportedly wanted to stay out of the limelight, according to his manager.
The Formula One driver was recently taken to a Paris hospital to receive a stem cell transfusion from French surgeon Philippe Menasche, Sky News reports.
The 50-year-old sustained serious head injuries after a skiing accident in the French Alps back in 2013.
Since his accident, his family hasn’t shared his health status. And the father-of-two, who’s been receiving treatment at his family home near Lake Geneva in Switzerland, hasn’t been seen in public since, Mirror reveals.
While speaking to media professionals in March 2016, Michael’s manager, Sabine Kehm, opened up about why the family hasn’t been updating the public on the driver’s health, according to RSVP Live.
"In general the media have never reported on Michael and [his wife] Corinna's private life," Sabine said.
"When he was in Switzerland, for example, it was clear he was a private individual.
"Once in a long discussion Michael said to me: 'You don't need to call me for the next year, I’m disappearing.'
"I think it was his secret dream to be able to do that some day.
"That's why now I still want to protect his wishes in that I don't let anything get out."