The tiedown bars look like a homemade version of the Torklift principle. You can see 3 of the 4 tiedown points on the picture - none of them seem to be badly bent, so they held up good. All of them have some length of chain dangling. The chain used may have been of the open/non-welded link type, and not strong enough to hold the camper in place.
The damage on the truck looks like a side wind from the left started to roll the truck & camper to the passenger side, the driver's side tiedowns gave way, and the camper rolled over the passenger bedside to the right. The driver may have tried to correct the roll-induced curve by steering away from it, making things worse. Or maybe the specific road conditions just conspired against them.
How the camper came to sit upright like it does is hard to understand, though.
In any case, it looks like no one was hurt and the truck needs a new bed and maybe new seat covers. The camper looks like it held up pretty good, too.
Many moons ago, there was a video on our local forum that showed such a situation developing from inside the truck cab. Luckily, they were able to get the truck & camper back on all four wheels without accident. Watching it (with sound) was ... interesting.
2014 Ford F350 XLT 6.2 SCLB + 2017 Northstar Arrow