"He's not mad." It was an instant reaction to the comment, she was defensive on the behalf of Jefferson because she knew he wasn't mad, just that there were complications that had affected how his mind worked on occasion. "He's just... been through a lot."
Between just how fragile he was before they ended up here, and then the possession and the sleep deprivation, Emma would challenge anyone not to crack a little. "Something that promotes positive thinking, something to protect against darkness I guess." She wasn't trying to fix Jefferson, not like he'd proposed when he'd practically broken from anxiety and stress. She was just looking for something to help.
"And anything in there to like, stop from possession again? I think that'd help a lot too." At the very least it'd give him a sense of safety.