Haven't seen a thread about this. The last band Billy was in - the Co-Dependents- was a good one, and had one of the best band names ever.
Here's a cut and paste from one obit I found online.
Billy Cowsill, the former frontman of the popular '60s family band the Cowsills and who more recently had been an integral part of the Calgary roots music scene, died on Friday night at his home in the Alberta city.
Though no cause of death has been released, Cowsill had battled a series of health problems in recent years, including emphysema, osteoporosis and Cushing syndrome. The 58-year-old also had a history of drug and alcohol problems that his brother Paul told the Providence Journal newspaper had "caught up with him."
The Cowsill family was in Rhode Island for the weekend to hold a memorial service for another brother, 51-year-old Barry, who drowned in the aftermath of Hurricane Katrina in New Orleans in September. His body was discovered on a New Orleans wharf on December 28.
The Cowsills' hits included "Hair," "The Rain" and "Indian Lake." They had their own television special, made milk commercials and were regulars on Las Vegas stages before breaking up in the early '70s. The group included parents Bud and Barbara, daughter Susan and brothers Billy, Robert, Richard, Barry, Paul and John. They were the inspiration for the '70s TV series, The Partridge Family.
Billy moved to Canada 35 years ago where he formed Blue Northern and the Blue Shadows. He co-fronted the latter mid-'90s group with Jeffrey Hatcher, formerly of The Big Beat. Sony Music Canada released two acclaimed albums from the roots-rock/country group.
More recently, Billy was a member of The Co-Dependents with fellow singer/songwriter/guitarist Steve Pineo, bassist Tim Leacock and drummer Ross Watson. The band released two live albums with a handful of original songs and a slew of good-time classic rock 'n' roll, country, rockabilly and R&B covers.
Billy, who had been working on degrees in both psychology and music education, is survived by two sons, Travis and Del.