Wangji has to swallow a lump at the mention of his son, so young and small and vulnerable. He nods,
"I do not remember much of that time but A-yuan is something. It is distressing to picture him alone without us." More than that, the idea that his sect is missing their leader and himself if a daunting one.
"I can see why you would be anxious to return home."

He looks up at his brother with sad eyes full of understanding.
"Thankyou for trying to get back. And for trying to be there for us both."
It won't help Xichen to feel less guilty but it should be said.