Question: Who were the parents of the singer, who covered the song "So Sad About Us" and has a half-brother named David Cassidy?

full_context: Document 1: So Sad About Us: "So Sad About Us" is a 1966 song by British rock band The Who, first released on the band's second album "A Quick One". Originally written for The Merseys, "So Sad About Us" has likely been covered more frequently than any other song on the album; according to the All Music Guide, it is "one of the Who's most covered songs". Shaun Cassidy, Primal Scream, The Breeders, and most notably The Jam and Dexter Romweber Duo (with backup vocal by Mary Huff of Southern Culture on the Skids) are among the many artists who have recorded studio versions of the song.
Document 2: Ian Paul Cassidy: Ian Paul Cassidy born November 4, 1964 in Harrogate, West Riding of Yorkshire) is an English actor who has appeared mainly in American and Australian productions. In 2000 he played Cracker Bob in "" and in 2001 he had a starring role in the drama series "The Beast", which was cancelled after five episodes. Cassidy first came to fame as the host of Australian television show "Kids Company", on Channel 10. He also appeared in many Shakespeare productions across Australia. During the 1980s he participated in a number of Australian independent films. During the first years of the 1990s he appeared in many U.S. films like "For the Boys", "Wind" and "In the Line of Fire", and Dimension Film's Sci-Fi :"". He has mainly appeared in American television series like "The Pretender", "EZ Streets", "", "Walker, Texas Ranger", "Drake & Josh", "Desperate Housewives", "Numb3rs", "24", "The Pacific", "Monk", "The Bold and the Beautiful", "The Young and the Restless" and numerous others. He has also appeared in many Video Games for MachineGames, including the highly acclaimed "" as Bobby Bram.
Document 3: Shirley Jones: Shirley Mae Jones (born March 31, 1934) is an American singer and actress of stage, film and television. In her six decades of show business, she has starred as wholesome characters in a number of well-known musical films, such as "Oklahoma!" (1955), "Carousel" (1956), and "The Music Man" (1962). She won the Academy Award for Best Supporting Actress for playing a vengeful prostitute in "Elmer Gantry" (1960). She played the lead role of Shirley Partridge, the widowed mother of five children, in the musical situation-comedy television series "The Partridge Family" (1970–74), which co-starred her real-life stepson David Cassidy, son of Jack Cassidy.
Document 4: Shaun David Barker: Shaun David Barker is an Australian born talent manager, marketing executive and executive music producer. He manages and markets Australian DJ’s including Timmy Trumpet, Stafford Brothers and tyDi, who have all been voted the number 1 DJ’s in Australia at the ITM Awards.
Document 5: A Quick One: A Quick One is the second studio album by the English rock band The Who, released on 9 December 1966. The album was also released under the title Happy Jack on Decca Records in April 1967 in the United States, where the song "Happy Jack" was a top 40 hit.
Document 6: Shaun Cassidy: Shaun Paul Cassidy (born September 27, 1958) is an American television producer/creator, screenwriter, and former singer and actor. He is the eldest son of Shirley Jones and Jack Cassidy. His older half-brother is David Cassidy.
Document 7: The Partridge Family: The Partridge Family is an American musical-sitcom starring Shirley Jones and featuring David Cassidy. Jones played a widowed mother, and Cassidy played the oldest of her five children who embarked on a music career. It ran from September 25, 1970, until March 23, 1974, on the ABC network as part of a Friday-night lineup, and had subsequent runs in syndication. The family was loosely based on the real-life musical family The Cowsills, a popular band in the late 1960s and early 1970s.
Document 8: The Who Tour 1966: The Who Tour 1966 was a series of performances and tours by The Who, supporting releases such as "My Generation" (album and single), "Substitute", "I'm a Boy", and "A Quick One".
Document 9: David Cassidy: David Bruce Cassidy (born April 12, 1950) is a retired American actor, singer, songwriter, and guitarist. He is known for his role as Keith Partridge, the son of Shirley Partridge (played by his stepmother Shirley Jones), in the 1970s musical-sitcom "The Partridge Family", which led to his becoming one of popular culture's teen idols and pop singers of the 1970s. He later had a career in both acting and music.
Document 10: Bald Headed Woman: "Bald Headed Woman" is a traditional blues song covered and released by The Kinks on their eponymous debut album in 1964 and The Who in 1965 as the b-side of "I Can't Explain". It is claimed that Jimmy Page, as a session guitarist, played lead guitar on "Bald Headed Woman" on both The Kinks and The Who versions. However Page is officially credited with playing 12 string acoustic guitar on two tracks on The Kinks' debut album, "I'm a Lover Not a Fighter" and "I've Been Driving On Bald Mountain" and possibly on the b-side "I Gotta Move", but not on "Bald Headed Woman".
Document 11: Boris the Spider: "Boris the Spider" is a song written by The Who's bass guitarist, John Entwistle. It appears as the second track of their 1966 album "A Quick One". This song is claimed to be Entwistle's first composition, and became a staple of live shows. This song, along with "My Wife", "Heaven and Hell" and "The Quiet One", were Entwistle's biggest songs to perform live. "The Quiet One" was written to replace this song and "My Wife", which Entwistle had become quite tired of singing. Though this song was popular, it was not released as a single in the US and the UK. In Japan, "Boris the Spider" was released as the B-side to "Whiskey Man" in 1967.
Document 12: Please, Please, Please, Let Me Get What I Want: "Please, Please, Please, Let Me Get What I Want" is a song originally performed by British group The Smiths. It was released as the B-side of "William, It Was Really Nothing" in 1984 and later featured on the compilation albums "Hatful of Hollow" and "Louder Than Bombs". The song has been covered by several artists, including The Decemberists, The Halo Benders, Franz Ferdinand, Elefant, OK Go, Deftones, Rob Dickinson, Emilie Autumn, Amanda Palmer, Hootie & the Blowfish, Muse, Cameo, Kaia Wilson, Third Eye Blind, Kate Walsh, The Dream Academy, Josh Rouse, She & Him, Slow Moving Millie, William Fitzsimmons and Sarah Darling, also, the chorus has been featured in a The Weeknd hook. British band Clayhill have covered the song and their version can be heard at the end of the Shane Meadows film "This Is England". Canadian electronic artist Venetian Snares also sampled the original song in "Nobody Really Understands Anybody". Canadian PBR&B singer The Weeknd sampled the song's chorus for the bridge for his song "Enemy". The song has become one of the most well known Smiths songs despite it only being a B-Side and it is often played by Morrissey during shows.
Document 13: A Quick One, While He's Away: "A Quick One, While He's Away" is a 1966 medley written by Pete Townshend and recorded by The Who for their second album "A Quick One". The song also appears on the album "BBC Sessions". In the performance on their "Live at Leeds" album Townshend calls the nine-minute "epic" track a "mini-opera" and introduces it as ""Tommy's" parents".
Document 14: Shauna Robertson: Shauna Robertson (born circa 1975) is a Canadian film producer. She has worked frequently with Judd Apatow, and has produced a number of films for Apatow Productions, including "", "The 40-Year-Old Virgin", "Knocked Up", "Superbad", "Forgetting Sarah Marshall" and "Pineapple Express".
Document 15: Happy Jack (song): "Happy Jack" is a song by the British rock band The Who. It was released as a single in December 1966 in the UK, peaking at No. 3 in the charts. It peaked at No. 1 in Canada. It was also their first top 40 hit in the United States, where it was released in March 1967 and peaked at No. 24. It was included on the American version of their second album, "Happy Jack", originally titled "A Quick One" in the UK.
ground_truth: Shirley Jones and Jack Cassidy