It doesn't really matter if he hears a difference. Good for him I'd say, to each his own. :)
This isn't a "all cables are identical" or similar debate though, don't get that impression. I'm telling you though that within the domain of a computer, everything is fully predictable and follows a strict set of logic. I am a professional programmer and analyst since the early 90s so I know very well how computers work. All bits are equal, yes. Audible differences can only occur if you treat those bits in some fashion, or somehow manage to corrupt them in the process. The latter is certainly possible given a sloppy software design, but I'd say it's quite rare. Use a good and well-respected player such as Foobar 2000 and I can guarantee you that there is zero difference between any lossless formats.
As soon as the bits leave the computer domain however, all bets are off. Typically this is via a digital output on the computer to an external DAC. From the point where the bits starts travelling from the digital output, they are susceptible to jitter. This is when you enter the world of hifi. Not before!
Still, I believe the confusion comes from a lack of understanding how data compression works, and a default prejudice against compression. "Surely an uncompressed file sounds better". :)
By the way that link you're posting doesn't work, it looks truncated?
