dee dee warwick, dionne's sister. whitney's brother gary, who also claims he was abused, says taking part in the documentary felt like therapy. >> how hard was that to talk about the things that went on? >> i mean, kev, it's long overdue, man. it's long overdue. there's no more secrets, no more hidden agendas. >> can i ask you one more question? this is real, man. >> the movie includes interviews with bobby brown and whitney's mother, sissy mouse ton. >> we miss it. there's no other voice like that. ♪ >> listen to me, this documentary is so incredibly honest and unflirchling. by the way, gary reveals that he too was allegedly abused by dee warwick. it is something else. later i sit down with whitney's sister. the drug abuse and the sexual assault are questions addressed in this film. >> i'm so glad you asked all those questions. stuff we always wanted to know. >>> well, there's also a new hbo documentary taking us inside the mind othams. the beloved comedian was celebrated by friends and fellow comedians at its emotional premiere last night. >> we were the best of friends, even closer than people could >> it's really hard because he did it because he can't -- he had no choice. >> it's just a giant, giant loss. >> bob saget, unable to hide the emotion, joined legendary comics like brad garret, kevin nealon, and wung one of robin's closest friends, billy crystal, to premier the new hbo documentary, "robin williams: come inside my mind." >> i was 18 1/2, and i had to follow him on an open mike night. and, uh, i think that's what started the 20 years of drinking. >> the film is told through both robin's own words and by tho

. >> reporter: in the film, it's alleged cousin dee dee warwick who died in 2008 was the abuser.ine addiction. gary admitting he often got high with his sister but realized she was in trouble when she began missing shows. because she was high. >> because she was using somewhere or coming down from using and not being able to perform at the best of her level. >> reporter: for the first time, the inner circle sharing details about her close personal relationship with creative director robin crawford. and houston's tumultuous marriage to singer bobby brown. some saying he felt eclipsed by his wife. >> when you got people in the media talking about mr. houston instead of mr. brown, you know, he let it get to him. >> can i ask you real quick, ms. houston? >> mrs. brown. >> mrs. houston brown. ♪ bobbi, my baby >> reporter: but perhaps the most poignant moment, houston improvising and singing to her daughter bobbi kristina. who at age 22 would eerily die just like her mom three years after houston's death. ♪ you don't have to worry about a thing because i'm standing right by your side ♪