Whitney Houston's family opens up to Oprah

(CBS News) It's been nearly a month since Whitney Houston died, and now three members of her family are breaking their silence in an intimate interview with Oprah Winfrey.

"CBS This Morning" had a preview of this weekend's Oprah-exclusive, in which Houston's sister-in-law, manager and confidante, Patricia Houston, talks about attending a party with Whitney a few days before her death and acting as the singer's "sister-protector."

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"I know that she wanted to go out and she wanted to have a good time," Houston said. "[I was there to] make sure she was going to be OK."

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Houston's battle with drugs and addiction had been an ongoing saga splashed across the tabloids for years and in 2011, she returned to rehab for treatment.

Complete coverage: Death of Whitney Houston

You can see the entire interview on "Oprah's Next Chapter," Sunday night on OWN.