A Dutch prince hit by an avalanche while skiing off-trail in Austria last week suffered massive brain damage and may never regain consciousness, his doctors said Friday.

Johan Friso, the second of Dutch Queen Beatrix's three sons, was buried for 25 minutes before rescuers found him. It then took nearly 50 precious minutes to reanimate the prince after he was pulled from the snow, time that may have cause permanent damage, said Dr. Wolfgang Koller, head of trauma at the Innsbruck hospital where he is being treated.

"It is clear that the oxygen starvation has caused massive brain damage to the patient," Koller said. "At the moment, it cannot be predicted if he will ever regain consciousness."

The 41-yaer-old Friso, who is married and has two young daughters, will be moved later to a rehabilitation clinic for further treatment. But Koller cautioned that it may take years before he awakens from his coma -- if he ever does -- and any recovery from such significant brain damage is a process of "months or even years."

Friso was skiing off-trail in Lech, Austria, despite avalanche warnings, with a childhood friend from the alpine village the Dutch royal family has been visiting each winter for years.

The friend was carrying an avalanche "air bag" and escaped without serious injury. Friso was found with the help of a signaling device he was carrying and flown by helicopter to the Innsbruck Clinic.

But "50 minutes of reanimation is extremely long. You could say too long," Koller said.

The doctor said that due to protocols for minimizing brain damage after such an accident, it had only been possible to conduct an MRI scan of Friso's brain on Thursday.

"We had hoped that the slight cooling of the patient would protect his brain from too serious damage. Unfortunately this hope was not fulfilled," he said.

Friso is in a coma, a state of unconsciousness in which a person cannot be awakened with external physical or auditory stimulation. There are different levels of unconsciousness and unresponsiveness depending on how much brain function there is. Doctors did not give further details of Friso's diagnosis.

Members of the family, including Beatrix, Friso's older brother Crown Prince Willem-Alexander, and others have traveled to and from the hospital in a somber vigil. His wife, Princess Mabel, has worn black.

They appealed Friday for the media to respect their privacy. In a statement, the family said it "needs space to learn how to deal with Prince Friso's health situation and to adjust their lives to it."

Prime Minister Mark Rutte's office said he called the queen Friday morning to tell them the "country sympathizes deeply with the royal family in this time of concern and grief."

The queen has said that the family has been moved by the "countless" messages of condolence and encouragement they have received.

Friso, who worked for years as an investment banker for Goldman Sachs, had previously been a relatively low-profile member of the highly popular Dutch royal family.

The most public period of his life before the accident came during his engagement to Mabel, a Dutch woman whose maiden name was Wisse Smit.

She worked for George Soros' Open Society Institute and was seen by the queen as an ideal daughter-in-law. But during her vetting to join the royal house, the pair decided not to disclose the full extent of a university friendship she had with drug baron Klaas Bruinsma, who was later slain in a gangland killing.

Wisse Smit said she hadn't fully understood who Bruinsma was at the time. But as details of their former friendship emerged in the Dutch press, then-Prime Minister Jan Peter Balkenende said he wouldn't propose the law needed for parliament to approve Wisse Smit's entry to the royal house.

According to the Dutch constitution, all royals require a law to be passed approving their marriages.

The couple acknowledged being "naive and incomplete" in what they told Balkenende.
Friso and Mabel decided to marry without seeking parliamentary approval, knowing the decision meant Friso would be cut from the royal house and line of succession. They are still members of the royal family, and bear honorific titles of Prince and Princess of Oranje-Nassau.

Since his marriage, Friso has served on various supervisory boards, worked for charitable organizations and helped found a low-cost airline. In 2011 he left a position as managing director at investment firm Wolfensohn & Company to became the chief financial officer of Urenco, the European uranium enrichment consortium.

The couple lives in London with their two daughters, Luana, 6, and 5-year-old Zaria.