I think he got tired of our arguments regarding "God" and the Bible, with me just spewing out JW doctrine without ever backing it up. I'm very thankful he did, because it made me realize what a hole I was in.
It really is a 'slap in the face' moment, isn't it, when you realize you can't no longer hide behind a belief you don't really believe in anymore?
I have many family members who are doing the 'I don't know' position when asked, but little by little I see them coming out of it. :)