I don't believe if anyone really know something others don't know. It seems that the earth will rotate without anybody. I would be happy and positive to have an interview with him.
Even if he tricks you to teach something, which I highly doubt it, I would still perform best I could do. There is no loss for you to teach him to perform. At least he would give you a good recommendation letter if you ask him in the future. Or he might think about you if there is true openning in the future.
Just my 2 cents.