I received help by contacting support live chat in less than 10 minutes. They did not tell me anything beyond what the support ticket said - however something did catch my eye. One of the requirements being the person's account must not have been "subscribed / logged into more recently than the last three months."

Logged in meaning "logged into the game". Does this mean logging into your character in the world or simply logging into the game client? The only reason I can guess might make my friend ineligible is he did log into the game client to try and download/install the game early which promptly told him he needs to subscribe in order to receive updates. However, depending on their account activity monitoring... I could see this as flagging his account as 'being logged in'.

My advice for anyone in the future - try to make sure your friend avoids logging into game client at all. Logging into mog station is okay.