What is a character trait of Mr. Frampton Nuttel from "The Open Window"?

Mr. Frampton Nuttel is a visitor to the area and to the home.  He suffers from a "nerve condition" and thus could be described as neurotic.  He comes with letters of introduction from his sister and has come to the countryside to relax.  But he proves to be quite gullible when the niece tells him the false tale of her aunt's widowed state.  As the hunters return, Frampton freaks out thinking that he has seen a ghost. Mr. Nuttle is shown as quite naive as he frantically flees the house.