Nick Gordon claims Bobbi Kristina Brown turned to drugs to help her cope with Whitney Houston's death.
According to Nick, 25, Bobbi was a "social" drug user before Whitney drowned in a bathtub in 2012 following a massive heart attack caused by years of cocaine abuse but things soon spiralled out of control.
He told Dr Phil that Bobbi's "social" drug use became "really bad" and added: "It's unfortunate but at the time it's the only way we knew how to deal with what happened."
Nick also hit out at those who have blamed him for the deaths of Whitney and Bobbi, 22, who passed away in similar circumstances, three years apart.
He said: "Regardless of what everybody thinks, I made Krissy and Whitney's last few years on earth as happy as they would be.
"I gave them somebody to trust to, to talk to, to be there, someone genuine."
And he was especially scathing about Bobbi's father Bobby Brown, saying: "(Bobby) hurt his own daughter, not me. I was the one there for her while she was dealing with him not being there. He's not a reasonable person so I'm not planning on talking to him and I really don't want to."
Bobbi Kristina died in 2015, almost six months after she was found unresponsive in her bathtub.
Nick's two-part interview on 'The Dr Phil Show' will air on Thursday (28.04.16) and Friday (29.04.16).
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