Hoping, too. Doesn't look good.... Why would he have left the road in the first place?
It probably was going up over a ridge and he saw downhill as an easier path. Going downhill makes sense unless conditions are severe and you are unsure whether you are trapping yourself in doing such. In this case, that probably happened.
What a shame.
Just speculating, but since they got lost trying to follow the roads coming in, perhaps he beleived the road was marked well enough with signs for him to find his way out of the maze. If you look at topo maps or aerial photos, the area has all kinds of winding paths, many of them mile+ long dead ends. Perhaps he knew the river was heavily used in summer by rafting groups and had campsites (shelters) along it. Maybe he went to gather some berries, slipped down a steep slope, and then decided to keep on going down (remember, when he left he told his wife that he would be back in 5 hours.) They had been stuck for 7 days on the road, perhaps he concluded that he had to increase the odds by trying something other than the road (since the family was still with the car in case rescuers finally covered the roads), knowing that heading downriver would eventually lead him to the lodge. Maybe he just decided that doing the same thing wasn't go to work. Or maybe he started to lose his sense and logic due to hunger and cold. I dunno.
Should be: Just speculating, but since they got lost trying to follow the roads coming in, perhaps he believed the road was NOT marked well enough with signs for him to find his way out of the maze.