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."

"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."

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.

To see the preview clip, watch the video in the player above.