"I know right." He was about to say the only thing missing was Mom, but Sam's mom wasn't Adam's mom, so he thought better of it. No need to rub salt in a wound that would never heal anyway. Sam was still bitter toward his dad about the fact he'd kept Adam in the dark about everything, and had kept Sam and Dean in the dark about Adam's existence. Maybe they could have helped him. Maybe...
There were a lot of maybes and what ifs and none of them mattered. What mattered was that Adam and his mother had died horrible deaths they were completely unprepared for, completely vulnerable to. And it could have been prevented. Maybe.
But Adam was here, a survivor of hell, with an angel riding shotgun in his head. Sam knew how exhausting that could be. "If you need to vent at someone, I'm your guy. As much as I love dad, I have a thousand grievances with him."