He doesn't want to talk to you... Just kidding! Are you able to receive emails?
If so you would be notified if your email server couldn't send them, like "unable to send.... and then the reason."
Check by opening free account with gmail.com or yahoo.com and trying to send one to that account from your existing account. If it works then its your son's problem.
First though, have him check his "Spam" folder. Perhaps your emails are being send there.
Mr. P, October 2009