It sure didn't sound like he knew her. But it did sound like he was excited? Perhaps it was the time (ugh) nonsense the Tavernkeeper mentioned. He was from before she was born, maybe.

"Yes." She confirmed, stepping forward. "I am Melinoë, daughter of Hades and Persephone. I have a brother, Zagreus, and I've seen a portrait of you — I look at it every night."