Sam didn't know what he'd been expecting, but it wasn't that. Although of course in retrospect, it made sense that his dad would want to tell him about Adam. He was, actually, a little impressed that he'd said as much without having to be pressed. He couldn't expect that it would be easy news to hear.
But it wasn't news, it wasn't anything new. It was different hearing it from his dad's perspective rather than the ghoul's, or Adam's, so he could appreciate it anyway, but he waited for John to pause and then spoke up, letting him off the hook of having to tell an uncomfortable secrets. "Yeah. I know about Adam."
Of course, that meant that he was now the one in the position of having uncomfortable information to share, and it was worse news than Adam's simple existence. "Dean and I met him. He... didn't get to be spared from all the crap that comes after our family, either." He hadn't even lifted his fork yet, and didn't, because guilt had momentarily ruined his appetite. He stared down at his plate, thinking about Adam in the pit, because of them.
Because of the angels, he reminded himself, hearing the words in the voice of his father when he'd been here younger. They'd both agreed to blame the angels, then-- but of course he wouldn't remember that now. Taking a deep breath, he finished, "And we couldn't save him. We did try. I'm sorry."