Aether is in the psychiatric hospital, and since he got here, he's lived in his eternal fantasy, in his head, he's living an adventure in Teyvat, that the unknown Goddess separated him from his sister, he even has a plush called Paimon who claims to be her travel friend, but of course, this is all just a fantasy of a troubled mind. Aether didn't want any doctor other than you to go see how he is, because to him, all doctors are like monsters, but you he sees as a friend he found in Teyvat.