Hi There,
.aud files are AudioLabel files and unfortunately AudioLabel is not compatible with Macs.
However, you can easily save your file as an image. You can then send him the image file which he can view and print.
Instructions on how to do this have been discussed on our Forum:
http://www.audiolabel.com/forum/viewtopic.php?f=2&t=156Let us know if you need more help.