What Darius seems to miss here is that at Persepolis, Babou gets to be the expert. He’s introducing his grandson to a historical site that’s close to his heart, and for now, he also gets to say what makes sense to him about Darioush the Great. When it comes to Darius’s depression and his teas, Babou isn’t an expert—he understands neither. He is, in a sense, trying to see the Darius he wants to see here, and this is confusing for Darius. But Sohrab’s friendship helps Darius feel okay with this strange interaction, as Sohrab makes Darius feel like it’s just fine to have complicated, conflicting emotions about all he’s experiencing.