Before he gives his own answer, Lan Wangji asks Shen Yuan. It seems that Aornis told him a great deal, relying on her own powers to keep him from retaining any of it, and that she did not account for the possibility of communication after death. That makes Lan Wangji inclined to believe that she has no particular power over the dead -- but Shen Yuan might know more.

"He doesn't know," he says a moment or two later, with an ephemeral little frown. "I am inclined to believe that her powers do not extend to the dead. If they did, she would have done more to stop me from contacting Shen Yuan each day. But I can't say for certain."