Play stupid games...
I've never met a person who carried and didn't know you couldn't do it whenever and wherever you want. It's drilled into you in the course and by everyone else that carries. I'm dubious that the OP's BIL didn't seem to know that. If I was a betting man, I'd wager he knew and took a chance making the drive anyway, then freaked out and being a more or less honest citizen sold himself out to the cop because he doesn't deal with cops not being a criminal. Most likely he messed up and now he's playing stupid on the law. Sadly we also all know from a young age that ignorance of the law is not a valid defense... I could be wrong. He could be soft in the head or some kind of unicorn that made it to adulthood, carries a gun with a CCW, and works on police stations but never heard or saw any of the signs or information on where you can and can't carry. Like I said, I feel for the guy, but I am dubious...