Are you sure? He clearly did post on that account and I couldn't search it.
Well, generally, the answer is yes. You do need to be logged on to post. But even if one's account is disabled, there's a potential workaround with a mobile device such as an iPad or iPhone.
Even if a player's account is disabled, if the person has previously accessed the discussion forum through the mobile device's browser, (for example, Safari on an iPad) and saved his username and password, it is possible that Safari will still have the person logged in to the account, even if the account is disabled.
I found this out about a year and a half ago. Another member got my account disabled. The details of why are irrelevant. For the 2 days or so my account was disabled, I was not able to post anything to the forums through the PC web browser. But I had previously accessed the forums through Safari on my iPad. The system would still allow me to post because it still had me logged on that way.
So, if he's aware of that workaround, then he would be able to post.