From the video it is only evident that the white car hit the Swiss man. It appears the Swiss man just drove across the road without looking and the white car assumed right of way.
I can only say that, 'this is Thailand', and apportioning blame may be a difficult pursuit by the Swiss man's partner. The white car had probably been driving down that railway road alt the way from the number 7 turn off, and just was assuming he had right of way at every junction unless blocked.
The only thing that would have stopped him would be if other traffic in front had come to a halt to allow other traffic across, otherwise they would just carry on driving without slowing down. That is why most of us crossing those sections, do so, with very cautious awareness. I always gave way if seeing traffic bearing down on me
Just a very sad situation.