As mentioned earlier the 1st time he tried to jump out of the plumes and it hits him at the end of the jump. The 2nd time he first rotates the camera and then starts moving which adds extra latency. You have to start moving immediately if you already have lag problems, so he might want to switch camera settings to legacy, so you can actually run to the back.
He could also try to play with a controller, since moving around is a lot easier with it, you have to get used to the cross hotbar layout though. Fast movement with a keyboard takes a lot of practice, so he may be better off with a controller.