"More recent familiarity," he answers, watching her intently. He wants to ask her if Lydia knows she's there. If they've seen each other. But it isn't his place to ask those kinds of questions, and especially not to Lydia's sister of all people.
"Which is only possible if we were in contact in some means besides reality." His eyes widen ever so slightly as realization dawns on him. "You were communicating with me in my dreams."