Bobbi Kristina Brown, 18, vanished following the star-studded service for the singer on Saturday.
It was reported that she was later found taking drugs with friends.
Her disappearance happened as 48-year-old Houston's coffin was carried out of church in New Jersey.
The aspiring singer — who has been taken to hospital twice since her mother's death, apparently suffering a nervous breakdown — failed to join her family at a meal after the service.
According to two sources close to the family, Bobbi Kristina was then discovered at a hotel allegedly "getting high".
A longtime family friend told US website The Daily Beast: "Everyone was freaking out and calling Bobbi Kristina's cell. It was so much commotion and activity after the funeral that Bobbi Kristina just slipped away. Ms Cissy [Whitney's mother] was beside herself."
The source said Bobbi Kristina was upset when her father, singer Bobby Brown, left the funeral service in a row over seating.
"It's a horrible situation for everybody," said the close family friend: "They tried to save Whitney, and it didn't work. Now with Bobbi Kristina, they fear the same thing is happening and they won't be able to stop it either."
