I have had the same issue with my 2012.
In my case I could hear the compressor running, but no air came to the bag. I decided to dig out the compressor (there's a lot of stuff to remove) and it turned out the issue was a broken axle from the motor to the piston rod, so the piston was not moving. I was fortunate to find a used compressor on Ebay to replace the broken one and all is good now.
Regarding your friends issue, it could be various causes. I would start by digging out the compressor and try hook it up to a 12V battery to see if it is alive. If it is, then use a multi-meter and try to locate how far along you have power. I hope it turns out fine.
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