I've watched the video through a few times. The blame is firmly placed on the truck driver for being on his phone.
But the car that he clips seems to merge from the on ramp directly across his front left corner, and actually nudges the truck to the right. It seems to me perhaps the truck would have hit him regardless. Is the car also/somewhat/exclusively at fault too? I am always very paranoid about how little a truck driver can see down the left side of their cab and never dwell in their blindspot. Thoughts?
 adding the link to this excellent short video demonstrating the extent of a truck drivers blind spot.
Also I would add I think there's zero excuse for a "professional" driver to not have a legal hands free kit these days.