Before doing anything, you will first have to determine his cult status.
Was he born-in or raised in it, or converted when he was older? Depending on which one he is, this will tell you what you can and can't bring up.
For example, if he was born-in and his parents were somewhat zealous JW's, then he should be familiar with 1914 and 1919, and possibly 1975 and the "generation" teachings. These are meatier subjects that you will want to discuss with him.
If he should happen to be someone who later converted, he will likely not be familiar with most of the dates and their significance. He is likely a JW by behavior and not by being convinced with the NWT (not the Bible) that the WT is God's channel of communication.
Good luck...