if he has a monitor like mine then he could just have it in pip mode (picture in picture).
And he would have the audio in from the wii connect into his pc.
Then its a matter of someone using the mouse to move it around a bit, then a slight delay where he turns on the sensor bar (using wireless sensor bar you can turn it on/off) at that point the cursor for the wii shows up in the PIP box.
Just one way it can be made
Perhaps I should make a video called , wii emulator on windows (unfolded)