A couple of things it could be. If you didn't talk to your friend, and just his wife-you could be experiencing what we call in the biz, "human-error" here. If your friend changed his E-mail and didn't tell his wife for any number of reasons, her information could be out of date. For example, she may no longer be physically residing in the same household as your friend. If your friend no longer wants his wife to have that info he might have changed it since they are separated. If he is the Account Owner on the E-mail, she might have been peeking into his E-mail *again, for a variety of reasons*.
I could go on, but you get the point. The only person you can really trust to give you a 100% accurate E-mail address is your friend; not a go-between (his wife!). And even then, as Mike said if you type it wrong and are off by one character such as a hypen instead of an underscore or the letter "l" and the number "1" which look a lot alike on the screen and keyboard, you could have typed it wrong. Having been an E-mail administrator for dozens of companies I've seen it all, but this sounds like simply a case of bad communication with your friend.
Unless he's hospitalized, in prison, or camping out in Siberia somewhere you need to get a hold of him and verify his E-mail address on the phone with him directly. The suggestion of having him E-mail you and you simply reply back will eliminate a lot of this. The other problem is that the bellsouth domain is often blocked by businesses, as that is a major ISP provider and some companies give those addresses out to employees. That means if your friend's address is a business E-mail and not a personal address it could be managed by his employer's IT department which means they could have all kinds of filters on incoming E-mails from unknown addresses which are then blocked by filters and automatic rules on their Mail servers (Your friend's employer).
Additionally, many companies today outsource their entire E-mail operation to IT companies who manage it and can use a variety of Mail servers including Unix/Linux Mail servers which are designed to block out any suspicious E-mails.
If the content of your E-mail includes any graphics images or suspicious links, they could be blocked by your friend's company via their IT department, Mail Server, or outsourced E-mail management provider.
Try this; after you talk with your friend on the phone, have him send you a plain text E-mail message such as a simple "hello" to you, and reply back with the same; a plain text E-mail message, again no graphics, so signature blocks with your funny icons, your company or business-logo etc. 99% of the time this will fix the problem. In the case it still doesn't and you discover after talking with your friend that he has a personal E-mail forwarding provider or his own Mail or Proxy Server running his E-mail, you might discover that
YOUR E-mail address is
NOT in his Address Book or Contacts.
**Have you changed your E-mail address in the last year or so since you've communicated with him???** In many situations, he may need to add you into those in order for your E-mail to get into his Inbox.
Trying most of these suggestions will almost always result in a fix. If you're still having a problem, you can do what Mike suggested, which I've also had to do, is to have him setup a temporary Gmail or Yahoo E-mail address *disposeable* and communicate with him that way. Most likely, he is doing something funny on his end or it's a human-error issue as I described above, and you need to speak with him directly to solve it.
Best of luck,
<<<<BIGBEARJEDI>>>>