Tim is Susan's accountant cousin, who comes to help her with her taxes.
Tim, born in 1979, knows a little something about Katherine Mayfair's mystery (the two had slept together when he was 16). It is first thought he finds interest in the fact that Dylan is about to turn eighteen years old and is constantly being observed by Susan just in case a relationship flourished. When Susan suspects that he is in bed with Dylan over a telephone conversation, she returns home to find he was in bed with Katherine. ("Sunday")