Of the millions mourning Whitney Houston's tragic Saturday death at age 48, no one was hit harder than Bobbi Kristina Brown.
"Her world will be shattered," a family source tells Us Weekly of the "Greatest Love of All" singer's 18-year-old daughter with ex-husband Bobby Brown.
An aspiring singer and actress with an impressive voice of her own, Bobbi "wanted to be just like her mother."
Although Houston was supportive of her daughter's dreams -- the pair had started working together on songs in the studio -- things frequently got sidetracked by the Grammy winner's ongoing struggles with addiction, and young Bobbi even took a "caretaker" role with her ailing mom.
"She idolized Whitney, which made always seeing her mom in disarray that much worse," the insider explains. (Houston, who finally divorced Bobby Brown, 43, in 2007, entered rehab last spring.)
"Bobbi was always by her side in everything she did," the source adds. "She was really her mom's caretaker and biggest cheerleader and biggest fan...I don't know how she will be able to go on."
Houston was found unconscious in her room at the Beverly Hilton Hotel Saturday afternoon; after unsuccessfully performing CPR, paramedics pronounced her dead at 3:55 p.m. Her cause of death is still unknown, but authorities said "no foul play" is suspected.