I think its obvious from the photos it is bent, three pictures head on. Anyway, it's unlikely he received it that way and it's very unlikely that it bent on its own. The gimbal is built like a tank.
So are you wanting to straighten it out or are you trying to figure out why it happened?
I'm fairly certain 3DR would not warranty, but you never know. At this point you got nothing to lose in attempting to straighten. I'm sure there is thread here that describes an effort for same. The gimbal arm is fairly strong, not sure of the actual material. I'd venture to bet you'd have one shot at straightening it out, otherwise the material would fatigue from the repeated bending.
Alternatively, he buys a new gimbal and back to happy flying.