Has he had any sort of softmod on there previously, so that bootmii has hopefully been installed, or is it a 'virgin' install
Try turning on the wii and holding down the 'reset' button, if bootmii comes up your in luck
I've bricked ours in the past while playing with wads but luckily had already softmodded it previously so managed to get bootmii to run and 'just' reinstalled the wads using wadmanager as I had corrupted the system menu by accident
Be aware that some mods are designed to work on very specific firmware, so that may have been where he went wrong if he tried to install on an eralier firmware
Just come across an issue with darkcorp 1.1 the first release, download the full installer. Apparently there was an 'issue' with the installer
Not that this may help your friend and his wii though ......