He said in the video that his channel was joining with IGN. JOINING, as if IGN needed his channel. And because of that, his channel was going to grow even more and have better videos.
Now I don't know if he didn't understand what he was getting into, or if he's an idiot, but did he actually expect he was going to have time to make videos for his channel and be in charge of the IGN Nintendo branch too? Or that IGN was even going to allow him to "share" the videos with his channel?
Needless to say, that was his last video on the channel.
Part of the responsibility falls on IGN to monitor what their employees are saying/doing and to set the record straight. Expectations should have been communicated clearly.