How Awful About Allan (1970)

Allan leaves paint cans and thinner next to a heater one night, which causes a fire that kills his father and disfigures his sister Katherine, and he goes hysterically blind. After an eight-month stay in the mental hospital, Allan comes to terms with his resentful feelings toward his father and sister and with the guilt that caused his blindness, so he can see blurry images. He takes his doctor's suggestion that he talk about his feelings into a tape recorder. He tells the machine how ambivalent he is about Olive, to whom he was practically engaged before the accident. He tells the machine that his resentment over his sister's near-incestuous relationship with their father has not gone away, especially after learning of her work raising money to get the great professor's name on a new wing of the library. But his main subject is his sister's mysterious new boarder, Harold Dennis, a university student who only speaks in a whisper because of a throat injury. He comes to believe that this boarder is out to kill him.