Recipient not receiving email to text messages

Igottaquestionforyou wrote:

all I can think is that it has something to do with his iPad being linked to the same account as his cell phone.

That is unlikely as the messages you're sending get turned into SMS/MMS messages and iPads can't, on their own, send or receive SMS/MMS messages. Everything has to go through iPhone .

I suggest that you have the person who doesn't get the messages contact AT&T. The problem may be on their end.

iPhones don't let you turn emails into text messages, and vice versa. This means you can't send an iMessage to someone's email address, or forward an email from your Mail app to their phone number. Even between iPhones, this feature isn't available.

While Apple doesn't offer built-in conversion between emails and texts, some carriers do provide this as a service. AT&T, for instance, allows you to send a text message by composing an email addressed to the recipient's phone number followed by "@txt.att.net".

Please contact your carrier if you have an issue with that feature that is allowed by AT&T