Coworker Controversy

Alright Folks- I've got a problem and I'd love some feedback. I work at a church not far from campus with 5th and 6th graders. My primary job is just to hang out and provide counseling and be a good role model. I lead a Wednesday night worship/high energy/playtime/crazy young life-esque event. So here's the conundrum. I have a coworker who has confessed to me that they are an atheist. They say that they dont believe in God, but that the reason they work in a church is because when they were in 5th and 6th grades, the church gave them a moral compass to guide them through the difficult adolescent years. My problem/question is, should we allow this person who doesnt believe in god (but who still gives messages using the bible, prays for the group as a whole and interacts these kids in a "Christian" atmosphere) to continue on working? My big issue is that this person is not bound by the moral code (read: the 10 commandments) that people who are Christians are, so therefore, they feel like they can partake in whatever they want to whether it be drugs, sex or other "immoralities" according to the bible. Is this ok? When I first found out about this, I was astounded, but at the same time, knowing this person to be a person of good character, I decided not to say anything. This has been a personal and moral debate for me since I found out. So the big question is- Out my coworker and take away something from them that they love (because I'm sure that if our bosses found out, this person would be immediately fired), or, keep keeping it a secret, in hopes that this person figure it out for themselves- Please send me your comments/thoughts/ etc!!!