Complex sentence: Sue allows Finn Hudson (Cory Monteith) and Kurt to plan Jean's funeral and help her sort through Jean's personal belongings, and agrees to have the glee club to perform at the funeral, as she believes no one will attend otherwise.
Split into simpler sentences: Sue allows Finn Hudson (Cory Monteith) and Kurt to plan Jean's funeral and help her sort through Jean's personal belongings. She also asks the glee club to perform at the funeral, as she believes no one will attend otherwise.