Sam hadn't said anything when he first saw the dents on the Impala. If Dean wouldn't talk to him about what he was going through, then Sam supposed the old Chevy was a decent outlet for his brother's grief. The car certainly couldn't have its feelings hurt. It was just an inanimate object, a gas-powered machine that had happened to have been in the Winchester family for a while. The only thing Dean's abuse of it did was cost them time while he banged the dents back out again. And it seemed like they had too much time on their hands these days.
Still, Sam couldn't help but feel, as he walked away, that he was turning his back on something much more than a banged-up car. Something more like his brother's beaten wife.