Hi,
I've had a failed update on my RNS too in the past,
if the touchscreen IS unresponsive, you can navigate the menu to update using the left/right buttons to the left of the cd slot and the 'i' or star button to the right of the cd slot to 'select'
best bet is to run the swl recovery, and to use a 'stock' firmware such as 2680, (2760 was the same firmware which caused my RNS to fail)
i'm assuming he has the correct CAN gateway in his car, worst case scenario he may need to replace the power supply on the RNS, on mine it only cost me the cost of the PSU and the tools to replace it.
good luck to your fellow rocco owner!