Whitney Houston's daughter Bobbi Kristina has received condolences from President Obama.

The 18-year-old is said to be "hysterical, exhausted and inconsolable" after losing her mother on Saturday afternoon.

Obama's rep said he sent his regards to Houston's relatives but was particularly concerned about the teen.

"His thoughts and prayers are with her family, especially her daughter," White House press secretary Jay Carney said today.

"It's a tragedy to lose somebody so talented at such a young age."

Meanwhile, an extended member of Whitney's family said that Bobbi Kristina is not doing well.

The late singer's sister-in-law's brother, Billy Watson, told Us Weekly that Bobbi is doing a little better after being hospitalised twice since her mother died but was understandably taking the news badly.

"Everything [was] stressful," Billy told the publication. "Her mama died, so she broke down. Nobody expected her to pass as quickly as she did. [Bobbi Kristina] had a nervous breakdown."

It was Bill's brother Ray, who worked as her bodyguard for 15 years, who found Whitney in the bathtub. He is said to be doing "OK" after the startling discovery.

Whitney was seen partying with R&B singer Ray J in the days before she died. Ray J's sister Brandy was a close friend of the Bodyguard star after they worked together on a remake of Cinderella in 1997.

"My heart is destroyed," Brandy said in a statement today. "I lost my idol and dear friend. My prayers go out to Whitney's family and her millions of fans around the world."

"Whitney the greatest voice of all time you are my angel and I will always and forever love you."

Coincidentally, Whitney died on Brandy's 33rd birthday and she was supposed to have performed at Clive Davis' pre-Grammy party but said she was in a "bad space right now."

The 48-year-old's body has been released to her family and is reportedly being flown back to her hometown in New Jersey on director Tyler Perry's private plane.