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

Context paragraphs:
Getting It in the Street: Getting It in the Street is the third and final release by David Cassidy on RCA Records and would also be the last album David Cassidy released in the United States until 1990 (with the release of "David Cassidy").  "Gettin' it in the Street" was released in Germany and Japan in November 1976, but did not reach the album charts.  The few copies that were pressed for the U.S. were released in July 1979.

Didn't You Used to Be...: Didn't You Used to Be... is the only album David Cassidy released on Scotti Brothers Records.  The album was released in 1992.  Originally titled, "Didn't You Used to be"? , is David Cassidy's ninth studio album.  The album features ten tracks which are all written or co-written by David Cassidy's wife, Sue Shifrin.

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.

David Cassidy: Man Undercover: David Cassidy: Man Undercover (the word "undercover" in the series title appeared at various times written as one word or two) was an American police drama starring David Cassidy, four years after his run starring in the "The Partridge Family", marking his first starring role since that series was cancelled.  The series was spun off after Cassidy starred in a special two-hour episode of "Police Story", titled "A Chance to Live," which aired in May 1978; this episode served as the pilot for "Man Undercover".

One Small Step: The Story of the Space Chimps: One Small Step: The Story of the Space Chimps is a 2008 documentary film produced and directed by David Cassidy and Kristin Davy which aired on History Channel UK and CBC Television.  The film chronicles the real story behind the early use of chimpanzees in space exploration.  The film was released on DVD in April 2008, after several delays.  David Cassidy is best known for producing the documentary "" on the Dixie Chicks, and the Disney Channel show "".

David Cassidy Part II – The Remix: David Cassidy Part II – The Remix or Dance Party Remix is a dance album from former teen-idol David Cassidy.  The album was released in 2007 and is a remixed collection of four of his Billboard singles and seven Partridge Family songs in a club music style (with three versions of "Come On, Get Happy").

David Cassidy (album): David Cassidy is David Cassidy's first U.S. album released in 14 years and was his only release on the now-defunct Enigma Records.  The album was released in 1990 with the featured single, "Lyin' to Myself."  "Lyin' to Myself" was the first top-30 hit for David Cassidy in eighteen years.  The album reached 136 on the Billboard charts.

Dreams Are Nuthin' More Than Wishes: Dreams are Nuthin' More than Wishes was David Cassidy's third solo album release.  It was released in 1973 and produced by Rick Jarrard on Bell Records.  It contains some cover versions, including John Sebastian's "Daydream", Peggy Lee's "Fever" and Nilsson's "Puppy Song"--whose lyrics make up the album title.  David Cassidy also did his version of the Partridge Family song, "Summer Days".

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.

Old Trick New Dog: Old Trick New Dog is a 1998 album from David Cassidy on his own Slamajama Records label.  In addition to new songs, it also features several remakes of songs from "The Partridge Family".  The single lifted from the album - "No Bridge I Wouldn't Cross" - was an Adult Contemporary Top 25 hit in the USA.  The track - "You Were The One" - was co-written by David Cassidy and Tony Romeo who wrote many of the most popular songs for Cassidy and The Partridge Family in the 1970s, including I Think I Love You, "Summer Days", "I Am A Clown" and "Sing Me".

Supporting paragraphs: So Sad About Us Shaun Cassidy
Answer: Shirley Jones and Jack Cassidy