How exactly was he accurate? It was widely speculated that the Big Ten was interested in Texas and possibly A&M. It was also later widely reported that Nebraska was being considered as well. He didn't exactly break these story lines. He did make a bunch of claims about specific details of negotiations that neither Texas nor the B1G has confirmed. Of course it could all have been 100% true and the situation was very fluid, as you say, or it could have been 100% made up on his part and we will never know the truth either way. He could very well have a source, but that doesn't mean his information is entirely truthful either.
Let's just say I find it suspect that one of the parties in a serious negotiation would leak the exact terms the other side was asking for on an internet message board, especially a message board for a team nobody cares about, like Northwestern. I also find it suspect that the B1G would dismiss, out of hand, the request of one of the most successful brands in college football (Oklahoma), especially if the request did not involve another school (OK State). Does any of this really sound plausible?