why his ass calling himself schizophrenic when he has no choice but to spend rest of his l...

Because Ilay made him have schizophrenic behaviors through trauma. He is realizing (he is delusional) that he thinks he wants to be with Ilay. He said it himself he was going back to him in the end because he wanted to. Its certainly more stockholm syndrome here but i can see why Tay thinks he is having Schizophrenic thoughts.