Elwood is younger than his sister, and their elderly mother doted on him. She left the entire estate to him when she passed away, which is another reason his sister feels she has to wrest Power of Attorney from him. He likes to invite people to supper at the home he shares with his sister and niece, regardless of who the people are or how long he's known them (usually just a few minutes). He is oblivious to class, race, religion, or any other social distinction, and in that time and place that's just plain awkward. Elwood seems innocent, perhaps a bit simple, and childlike in his reaction to people.
According to the movie, Pookahs are Celtic spirits with an odd sense of humor. The character of Wilson, an orderly at the sanitarium, discovers this when he looks the word up in the Encyclopedia. As he reads the definition aloud, the printed entry concludes with the words, “ . . . and how are you today Mr. Wilson?” “How am I?” demands Wilson. “Who in the encyclopedia wants to know?”