His best bet would be to create a free Youtube account.
Or, Soundcloud.
Then upload some videos or even just sound files.
Then post the links on here.
Not hard to do, just google "how to post a video on You Tube".
Sound files and videos can be done with most cell phones.
Even the cheaper ones have this option, at least sound.
Have him record from about 25-50 ft. from the call, as that is more realistic.
I agree, his biggest hurdle right now is not many will even look, let alone buy, without see or hearing his work. No matter how good he is, he needs to "get it out there", so people can notice him. If he is good, word of mouth will be his best advertisement after he sells a few. A lot of good call makers also post on ebay. He can then post the ebay links in the ebay advertising section on here.
Good luck.