Well, we choose how to interpret what we get told. I've been taught a lot of things but I never follow them as they're said. I do what I believe fits me the best. I can't follow rules that tells me what to do if I feel that "this is not me." Hence why I, even as a Roman-Catholic Christian, doesn't follow all our rules and live as I'm told - It's not me. The most important thing is our faith and not the way we act it out. As long as god knows we believe and love him, I believe that it's enough. If you know when you're committing a sin, then fine. But noone is pure and I also believe that the ones (the first priests) changed the way of the church to benefit them, and thus I change what I'm learning and getting taught to a way that I feel comfortable with and can live with.
If he feels that he can "sing" such a song, then fine. He chose it himself and he can still believe in god etc. Personally I feel a lot of flaws in the way of the bible etc so I can't stand doing exactly as I'm told.
We all have our own ways, the most important thing is that we respect them
