"I guess if he was carrying a radio he might but how many thru-hikers do carry one?"
Few, but perhaps a few more on that trail. I hiked most of the AT with a tech-challenged friend who asked me to pick out an MP3 player for him and help set it up. I put a lot of his music on for him, but what he ultimately ended up doing instead was listening to NPR and other stuff on the radio --- because on the AT you can so often pick up strong FM radio stations.
But practically speaking, I think very few thru-hikers are going to be listening to the radio, and often enough so as to pick up a rapid and significant weather forecast change in time to make a difference. What I did on the AT instead was to periodically get a weather forecast (internet via cell service). I certainly didn't (couldn't) do this every day, and I was definitely much more informed of weather forecasts than most thru-hikers as a result.
Until I watched the video I was a bit surprised to read that he was waiting in his tent. My inclination in really, surprisingly bad weather in there would be to try to get to the nearest (wooden) shelter, whether on the AT or somewhat off. When I went through the Smokies in March of 2010, they had tarp and similar plastic sheeting across the open fronts to make these shelters pretty good in the nasty weather. Unless you're really low on food (and sometimes even then), the smart thing in tough but transitory weather is to put on all your clothes, get in the sleeping bag, and wait it out. I had to do something similar in New Mexico last year.
In the sort of dump he got, however, it really is better to find some place to hunker down when it's that hard to move, and maybe even consider building some sort of snow shelter (debris hut comes to mind in those conditions, depending on how much snow was falling and how wet it was). Probably his solution of just putting up the tent was the right one, just wake up periodically to knock off accumulated snow on a tent that certainly was not 4-season.