what conclusion does the narrator draw about ushers mental state?

After Madeline's death, the narrator sees Usher becoming more and more withdrawn and more and more distant. Because he and Madeline were twins, he believes that a part of Usher died with her. Usher appears more and more confused and unable to communicate with the narrator. There is no question that Usher is having a mental breakdown, and the narrator is watching Roderick lose his mind as the story continues until the narrator leaves the mansion just before it all crashes down on the Ushers.