AceShowbiz - Whitney Houston's brother found it "therapeutic" to come clean about introducing the late superstar to drugs for a new documentary about her tragic life.

Filmmaker Kevin Macdonald interviewed many of the singer's relatives for Whitney (2018), but it's a revealing chat with her elder brother Michael, who confessed to introducing the I Will Always Love You hitmaker to drugs at the age of 16, which gives viewers a little history about the infamous substance abuse habit which ravaged her wholesome image.

Whitney's manager and sister-in-law Pat Houston, who is married to the musician's other sibling Gary Houston, reveals the candid discussion gave Michael the chance to work through his guilt and grief, no matter how hard it was to share something so raw.

"For him, I guess it was therapeutic to really talk about it, it was like a pressure cooker opening up for him to reveal (everything)," Pat told breakfast show Good Morning America.

"He was speaking about himself and talking about his sister, but he just needed to talk, and after sharing his sister with the world for over 30 years and just having to protect an image, that moment was his and he just talked.

"It was kind of a healing process for him as well".

Pat also used the interview to dismiss any claims of a rift between Whitney and her mother, gospel singer Cissy Houston, and shut down suggestions the icon's family had enabled her bad behaviour and let her down before her untimely demise.

"That is not true," Pat declared. "Her family has always been there for her, and I know that because I've been around for nearly 30 years".

Whitney, the first film to be officially sanctioned by her estate, premiered at the Cannes Film Festival in France in May and is set for release next week, ends July 06.

The superstar accidentally drowned in a Los Angeles hotel bathtub in February, 2012, with cocaine listed as a contributing factor in her death.