I understand the "follow the water" concept. I would not be very willing to head into a snowdrift to test it . . . of course, I wasn't there.
Well after 6 days without food and you just walked close to 10 miles on the road and you haven't found anything and the prospect of heading back to your family just to watch them die...I think would push anyone to solve the problem.
Ironically even though James died his efforts did lead to the rescue of his family - his footprints in the snow on the road.