Sam that knew the other her, the demon her, so well, She didn't know much about him beyond Castiel had said he called the demon friend and had some power to him.
Castiel had said he would come. But even so she had her holy water ready, she opened out the door, just slightly, and passed it out through.
"I need you to drink some before you can come in, always better to check" she told him quietly, so unlike the Ruby he knew already. "I'll open the door when you do"