Nasty. Looks like the LHS axle tube came out of the casing, which is pretty uncommon. It also appears that his field fix was too reinsert the tube back into the case, and realign it up (which he used chain and bottle axe to do) to get back on the road.
I'm guessing that when the tube popped out, that also subsequently broke the axle half shaft, requiring replacement. (he probably had a spare with all that kit).
At least the weather was good and he was in an open flat area. Years of washboard probably loosened that tube up. Might be a good spot to have fully welded on as a preventative!
I have a rear salisbury so this was a good heads up.