The source, who asked not to be identified, said media reports that Brown, Houston's daughter with singer Bobby Brown, had no brain activity were incorrect.

Bobbi Kristina's cousin Jerod Brown said on social media that doctors were not optimistic about the 21-year-old aspiring singer's chances.

"Though it seems the odds are against her, though doctors don't see any hope for change ... though it looks impossible for her to stand again STILL PRAY FOR BK," Jerod Brown said on Instagram, where he posts as yfkennedy.

Few details about Bobbi Kristina Brown's condition have been released. Her family has said she was fighting for her life after being rushed to a hospital in the Atlanta suburb of Roswell on Saturday.

Police said they responded to Bobbi Kristina Brown's home in reference to a drowning. Her partner and a friend found her unresponsive in the tub and performed CPR until help arrived, police said.

Houston, a six-time Grammy Award winner and actress who battled substance abuse, drowned in a hotel bathtub in Beverly Hills, California, on February 11, 2012. Authorities said cocaine use and heart disease contributed to her death at age 48.

Her daughter is receiving treatment at Emory University Hospital in Atlanta, according to CNN and other media outlets. The hospital would not confirm she was a patient there, but the hospital in Roswell that initially provided treatment said she was no longer under its care.

Family friend and gospel singer Kim Burrell told "Access Hollywood" this week that doctors had put the young woman in a medically induced coma to stop brain swelling.

Roswell police and an attorney for Bobby Brown have said they were investigating the circumstances that led to Bobbi Kristina Brown's hospitalisation.

In a video interview over Skype with E! News on Wednesday, Jerod Brown asked people to "let the detectives do their jobs" and to stop speculating about what had happened to his cousin.