The reason for John to faint at the end of the novel is his shock provoked by the wife’s mental state. He is a doctor and tries to treat his wife. The character prescribes the “rest therapy” to eliminate any distressing events from escalating the protagonist’s depression. This approach only leads the main character to insanity. John observes the results of his actions in full glory in the last chapter.
John is an abusive husband of the nameless narrator who faints at the end of the story. He is The Yellow Wallpaper’s antagonist. As a caregiver, he prescribes his wife the “rest therapy.” It is supposed to eliminate distressing events from the patient’s life. However, it only worsens her psychological health. The protagonist spirals out of control by obsessing over the yellow wallpaper. She doesn’t receive help confined to their home and the company of a controlling family. At first, the narrator finds it disturbing and asks John to remove it. He disagrees, implying that if he fulfills her wish, he would also confirm her paranoid concerns.
The main character proceeds to fixate on the paper in secret. Unsuspecting John acknowledges it as an improvement at first. The protagonist reaches the insanity peak during the last scene. She attempts to free the imprisoned woman behind the wallpaper. John realizes his mistake at the time. When he opens the door, he witnesses that his patient is tearing the wallpaper apart, creeping in the room, and crawling. This is a complete shock to him since John was sure that his wife’s mental state is improving. He faints, which can also symbolically signify that he gives up his power over the woman.