It wasn't that Sam didn't think of Dinah as family. It was a weird concept, but the idea was growing on him. This was as serious as he'd ever seen Dean with a woman, aside from Lisa. He was glad that Dean had found that, but that still didn't explain why she was tagging along on hunts.
"She's not even armed," he said, continuing with the hushed voice. "Martial arts skills aren't going to be a whole lot of good against a ghost."
It wasn't just that he was being an ass. He didn't want to see Dean's girlfriend get hurt. Granted, they were both here and could probably watch out for her, but didn't that sort of defeat the purpose of bringing her along?