Michael Schumacher team manager of Sabine Kehm has defended the family's decision to impose a complete secrecy on the medical condition of the seven-time Formula One (F1) champion as he continues to "make progress" from his horrific crash in the Fresh Alps 17 months ago that left him comatose.

Kehm said the near news blackout on the 46-year-old's condition is in line with Schumacher's wish to keep his private life, well, private.

"Michael always had strict rules that we worked out together," Kehm said and added, "He kept his job strictly separately from the private side, and he never deviated from that. There was never a 'home story', and no journalist ever had his phone number."

She added that Schumacher's family also has to deal with constant prying of photographers and paparazzi's who made a permanent camp outside of their home in Gland Lake Geneva where  Michael was flown in September by his wife Corinna to start his long process of rehabilitation.

Kehm continued, "It is never relaxed, because this is a permanent load," Kehm said and added that some photographers have even deployed low-flying helicopters near the Schumacher's home to capture some photos.

In a video interview released earlier, Kehm said Schumacher was making some progress in his rehabilitation process. "We are happy to say still he does improvement and I say this always considering the severeness of the injury he had," she said and added, "But of course it will take a very long time for everybody involved to fight, and we are happy to take this fight."

The interview was released to coincide with the launch of a watch that Schumacher helped design. The watch was presented near the F1 legend's home in Gland on Lake Geneva where is currently recovering.

But Kehm said that while Schumacher continues to recover from his near-fatal skiing crash in December 2013, the public "must always keep the seriousness of his injuries in mind."

Meanwhile, Schumacher's wife Corinna said she sold the family's vacation home and jet ski for $38 million because Michael will "never fully recover to enjoy them again," said Vine Report.

Since their father's crash while skiing with his 14-year-old son during a vacation in the French Alps, Gina Marie and Mike are excelling in their respective sporting activities, horse racing and car racing. Michael Schumacher hit his head on a rock in an off-piste area between two marked runs in Maribel. The German F1 driver sustained severe head injuries resulting from the crash.

Schumacher, who won 91 races in his storied F1 career, is listed as the wealthiest driver ever to have raced in Formula One, amassing a fortune estimated to be over $791.3 million.

But his family is also believed to be spending $152,000-a-week for his care, with the total amount spent for his rehabilitation has spiraled to more than $15.2 million.