Have either of you surfed behind another boat? It appears that he starts too far back and just doesn't have the board control to really "catch" the wave. He needs to get more on the balls of his feet and keep his weight forward on the board...
I participate in a lot of board sports and it took me 5-7 times out on an intermediate board before I could comfortably ride without the rope. Since then, I purchased a big ole landlock and can now get 1st timers up on the 1st day out. It was really frustrating for me to learn but now that I have a whole quiver of boards, we can get someone on a board that suits their ability level. You may be trying to start on a board that is a little too aggressive (it seems like it doesn't want to track super straight.)
As far as your weight setup, I'm sure some more people will chime in for a sunsport and a goofy wake. (edit You seem to be going pretty fast.... slower is going to be much, much easier. I speed up slowly until the whitewash just starts to fold over. The wave should follow the boat -- not run perpendicular to it like yours does. Moving the wakeplate up should make the pocket a little shorter and give you some more "push." This will make the sweet spot shorter but a little "sweeter" to start off on.
Good luck and keep us updated! You'll get there!!
Former owner of a 1987 Supra Saltare. Current owner of a Malibu 23LSV.