Question: who is the sibling of the cast member of The Eternal Grind?

full_context: Document 1: Exit Smiling: Exit Smiling is a 1926 comedy film directed by Sam Taylor and starring New York and London revues star Beatrice Lillie in her first (and only silent) film role and Jack Pickford, the brother of star Mary Pickford. The film was also the debut of actor Franklin Pangborn. This film is available on DVD from the Warner Archives Collection.
Document 2: Jack Standing: The son of stage actor Herbert Standing and brother of Wyndham Standing (1880–1963), who also was a famous actor in the early days of film, Jack Standing first appeared in Broadway musicals such as "The Belle of New York" and "Florodora" before he went to the Biograph Company in 1909. Because he was a handsome young man, he was quickly offered many roles and signed a contract with Sigmund Lubin in 1911. Like many others from the silent film, Standing was asked to play quite everything from passionate lovers to villains or old men. In 1915, he told the "Moving Picture World" magazine, "Spare me from being a one-type actor!" He appeared in more than fifty films. An incomplete print of 1915 Mary Pickford vehicle "Fanchon the Cricket", in which Standing co-starred, has recently been found. The teenage Fred and Adele Astaire allegedly made their screen debuts in this film. Standing's greatest success was the 1916 film "Hell's Hinges", where he played the weak-willed brother of Clara Williams.
Document 3: Johanna Enlists: Johanna Enlists is a 1918 silent film comedy-drama produced by and starring Mary Pickford with distributed by Paramount Pictures. The film was directed by William Desmond Taylor from a short story by Rupert Hughes, "The Mobilization of Johanna". Frances Marion, a frequent Pickford collaborator, wrote the scenario. The film was made at a time during World War I when sentimental or patriotic films were immensely popular. It was an early starring vehicle for Monte Blue, the male lead opposite Pickford. The film survives in several prints, including one at the Library of Congress.
Document 4: The Cry of the Children: The Cry of the Children is a 1912 American silent short drama film directed by George Nichols for the Thanhouser Company. The 29 minute picture, based on the poem by Elizabeth Barrett Browning about child labor, stars Marie Eline, Ethel Wright, and James Cruze. The film was released on 30 April 1912. Controversially it featured real footage of child labor in factories. The film was selected into preservation in the National Film Registry by the Library of Congress for being "culturally, historically, or aesthetically significant" in 2011.
Document 5: Mr. Flip: Mr. Flip is a 1909 American silent comedy film made by Essanay Studios, directed by Gilbert M. 'Broncho Billy' Anderson and starring Ben Turpin. The film is about a man going to various locations in town where he flirts with the women, and they in turn get revenge on him, causing him to leave their establishment. This film is believed to have included the first cinematic instance of a comedian being hit in the face with a pie, later known as the Pie in the Face, when Ben Turpin was struck. However, the pie Turpin was hit with was hand-held, not thrown.
Document 6: The Eternal Grind: The Eternal Grind is a 1916 silent drama film directed by John B. O'Brien, and starring Mary Pickford. The film is inspired by the Triangle Shirtwaist Factory fire, which took place in 1911.
Document 7: The Eternal Question: The Eternal Question is a lost 1916 American silent drama film drama starring Olga Petrova and directed by Burton L. King. It was produced by the production company known as Popular Plays and Players and released through the newly formed Metro Pictures.
Document 8: Ruth Donnelly: Though she made her first film appearance in 1913, her Hollywood career began in earnest in 1931 and lasted until 1957. In her films she often played the wife of Guy Kibbee ("Footlight Parade", "Wonder Bar", "Mr. Smith Goes to Washington"). Among her roles was the part of Sister Michael in "The Bells of St. Mary's", starring Bing Crosby and Ingrid Bergman. Years after her final film role, she returned to the stage, understudying Patsy Kelly in the Broadway revival of "No No Nanette" with old co-star Ruby Keeler and later appearing in the touring production starring Don Ameche and Evelyn Keyes.
Document 9: New York City: In 1904, the steamship General Slocum caught fire in the East River, killing 1,021 people on board. In 1911, the Triangle Shirtwaist Factory fire, the city's worst industrial disaster, took the lives of 146 garment workers and spurred the growth of the International Ladies' Garment Workers' Union and major improvements in factory safety standards.
Document 10: Behind the Scenes (1914 film): Behind the Scenes is a 1914 American silent drama film produced by Famous Players-Lasky, released by Paramount Pictures, based on the play "Behind the Scenes" by Margaret Mayo, and starring Mary Pickford as a struggling young actress. James Kirkwood directed and co-starred.
Document 11: Fascinating Youth: Fascinating Youth is a 1926 American silent romantic comedy film directed by Sam Wood. It starred Charles "Buddy" Rogers (in his feature debut), along with Thelma Todd and Josephine Dunn in supporting roles. Many well-known personalities made guest appearances in the film, judging a beauty contest in one scene, and Clara Bow makes a cameo appearance in her second film for Paramount Pictures.
Document 12: Laurel and Hardy: Prior to emerging as a team, both actors had well - established film careers. Laurel had appeared in over 50 films as an actor (while also working as a writer and director) while Hardy had been in more than 250 productions. The two comedians had previously worked together as cast members on the film The Lucky Dog in 1921. However, they were not a comedy team at that time and it was not until 1926 that they appeared in a movie short together, when both separately signed contracts with the Hal Roach film studio. Laurel and Hardy officially became a team in 1927 when they appeared together in the silent short film Putting Pants on Philip. They remained with the Roach studio until 1940 and then appeared in eight ``B ''movie comedies for 20th Century Fox and Metro - Goldwyn - Mayer from 1941 to 1945. After finishing their movie commitments at the end of 1944, they concentrated on performing in stage shows and embarked on a music hall tour of England, Ireland, and Scotland. In 1950, before retiring from the screen, they made their last film, a French - Italian co-production called Atoll K.
Document 13: Fine Manners: Fine Manners is a 1926 American black-and-white silent comedy film directed initially by Lewis Milestone and completed by Richard Rosson for Famous Players-Lasky/Paramount Pictures. After an argument with actress Gloria Swanson, director Milestone walked off the project, causing the film to be completed by Rosson, who had picked up directorial tricks while working as an assistant director to Allan Dwan. The success of the film, being Rosson's first directorial effort since he co-directed "Her Father's Keeper" in 1917 with his brother Arthur Rosson, won him a long-term contract with Famous Players-Lasky.
Document 14: Salome of the Tenements: The film, which was inspired by accounts of the real life of Rose Pastor Stokes, tells the story of poor immigrants living in New York's Jewish Lower East Side. It was shot in Paramount Astoria studios.
Document 15: The Eternal City (1923 film): The Eternal City (1923) is a silent film directed by George Fitzmaurice, from a script by Ouida Bergère based on a Hall Caine novel, starring Barbara La Marr, Lionel Barrymore and Bert Lytell.
ground_truth: Jack Pickford
sub_queries: The Eternal Grind >> cast member Answer: Mary Pickford
Mary Pickford >> sibling Answer: Jack Pickford