From what I can see, the Dx report looks just fine.
The only thing that puzzles me, is the Realtek 2nd audio device.
Could it be he has a HDMI connecting to a monitor / TV?
Me thinks it could be that all sounds go to the HDMI output, because it is somehow set to the default sound device?
Right-Click on the speaker icon in the lower right corner, select 'Playback Devices' and see which device is the 'default device', and once the USB headset is plugged in, whether that one is the 'default communications device'.
(I have no HDMI connections, so no sound devices showing up of that type...)
Also, on the tab 'Communications' (in the same screen), let him check whether the setting 'Do nothing' is selected ...
Good luck!