Police are still investigating the mysterious incident, which occurred August 2 while the 60-year-old man was on a highway about 60 kilometers (37 miles) west of Calgary, Alberta.
His wife and two others in their vehicle also were treated for minor injuries sustained in the ensuing crash.
German consular official Hubertus Liebrecht said the man, who has not been identified by police under Canada's strict privacy laws, remains in “critical condition” and “shows symptoms of severe and life-changing injuries.”
“The doctors were not able to remove the bullet from his brain, as they would have to cause further damage.”
He was to be flown aboard a special aircraft to Germany, “where he will be further treated in a hospital specialized on brain injuries,” Liebrecht said.
Police have ruled out road rage as a motive, suspecting instead the man was targeted because he was mistaken for someone else, Royal Canadian Mounted Police Constable Laurel Scott told AFP.
“None of the occupants of the (German tourist's) truck were the intended targets of the shooting,” she said.