Some info and photos from Find A Grave

https://www.findagrave.com/memorial/8294492/phillip_crosby

From Wikipedia (English):

Phillip Lang Crosby (July 13, 1934 – January 13, 2004) was an American actor and singer. He was one of four sons of Bing Crosby and Dixie Lee; the others were his older brother Gary, his twin brother Dennis, and his younger brother Lindsay. Phillip began his career singing alongside his three brothers and his father, Bing Crosby.

Early life and family

Crosby was born in California. He was educated at Bellarmine College Preparatory in San Jose.

Despite a promising start to life, the brothers were overwhelmed by their emotional problems, which resulted in heavy drinking. Their mother's death from ovarian cancer was hastened by acute alcoholism. Philip's twin Dennis and his younger brother Lindsay committed suicide with shotguns, in their 50s. Gary died from lung cancer in August 1995, aged 62.

Personal life

Crosby was married four times to:

1. Sandra Jo Drummond, a Vegas showgirl (1958–1963); two children, daughter Dixie Lee Crosby and son Brian Patrick Crosby (deceased).
2. Mary Joyce Gabbard, a Vegas showgirl (1964–1966); two children, daughter Mary Elizabeth Crosby and son Bing Crosby.
3. Georgi Edwards, a Vegas showgirl (1967–1969)
4. Peggy J. Compton (1972–1975); one son Phillip L. Crosby Jr., (a crooner in a musical quartet, which revitalizes some of Bing's old songs).

Death

Crosby died on January 13, 2004, in Woodland Hills, California from a heart attack, aged 69.