Valid question. 1st) He married into it I think. Obviously if he turned his investigative powers towards Mormonism it wouldnt last a week. But he wont since his wife is Mormon. Maybe someday though.....
I know people who started out to prove the church wrong and ended up joining and becoming good members.
No; he was able to get married because he got into SOME kind of 'religion'.
You can hear his testimoney on YouTube.