A member of Byrds, Buffalo Springfield, Crosby, Stills, Nash and Young, has died. He was 81. Crosby’s drug abuse may have exacerbated his medical problems, including a long battle with hepatitis C, which necessitated a liver transplant in 1994. He also suffered from type 2 diabetes and, in 2014, had to cancel a tour to endure a cardiac catheterization and angiogram. His mother, who was born Aliph Van Cortlandt Whitehead, descended from the prominent Van Cortlandt family. His father, Floyd Crosby, an Academy Award-winning cinematographer whose credits included the classic western “High Noon,” was a member of the Van Rensselaer clan. David attended Crane Country Day School in Montecito, California but flunked out. He completed his high school studies by correspondence and studied drama at Santa Barbara City College, but dropped out before to pursue a music career. He spent nine months in a Texas prison in 1982 on drug and weapons charges. In 1985, he was arrested on charges of drunken driving, hit and run, and possession of a concealed pistol and imprisoned for a year. By his account he quit hard drugs in 1986. But in March 2004, he was charged with criminal possession of a weapon in the third degree, as well as illegal possession of a hunting knife, ammunition and marijuana. He pleaded guilty and got off with a fine. Mr. Crosby had first become a father in 1962, with Celia Crawford Ferguson, but as young parents they put their son up for adoption. He had three other children: Erika, by his former girlfriend Jackie Gutherie; Donovan, by another partner, Debbie Donovan; and Django, with Jan Dance, his wife of 35 years. His brother Ethan killed himself in the late 1990s. His survivors include his wife and four children. In 1997, Mr. Crosby reunited with the son he had put up for adoption, James Raymond, who had grown up to become an accomplished pianist. With the session guitarist Jeff Pevar, they formed a jazz-rock band, which they cheekily called CPR.