Try if this works, regester his email at this site http://www.readnotify.com/
and then here is another link that trace emails but this one is not free http://www.abika.com/Reports/verifyemail.htm
use a linux box and then do a DIG command on the domain name DIG is Domain Information Groper. Also see this link to read so much more on email headers and the exact way email works http://www.expita.com/header1.html
and then here is a website where you can download very good software like this one http://www.emailtrackerpro.com/
try the demo and if you like it then search for it on http://www.piratebay.org
to download the full version for free. I hope this help a bit.