Michael Houston told Winfrey that he was the first person Whitney ever did drugs with, not the singer's ex-husband Bobby Brown. Michael admitted that he feels extremely guilty about his sister's death, but says he didn't quite realize just how dangerous drugs could be when he started getting high with Whitney.

"You gotta understand at the time ... the '80s ... it was acceptable," he told Winfrey. "It's painful ... I feel responsible for what I let go so far."

The iconic singer died in February 2012, and while the official cause of death was ruled to be accidental drowning, the Coroner's office confirmed that Whitney used cocaine immediately before her death, leading to a "cardiac event."

Though Whitney's brother admits he got her into drugs, the singer's mother, Cissy Houston, still blames Bobby Brown for her daughter's untimely death.

In her new book, "Remembering Whitney," Cissy writes that from the start she had doubted whether Brown was right for her daughter, and believes she may not have ended up so "deep" into drugs had they not stayed together.

"I do believe her life would have turned out differently," Cissy writes. "It would have been easier for her to get sober and stay sober. Instead she was with someone who, like her, wanted to party. To me, he never seemed to be a help to her in the way she needed."