Kristen Foster said she passed away on Sunday surrounded by her family and was “finally at peace in the arms of God”.
The tragic reality TV star was discovered unresponsive in a bathtub on 31 January and placed in a medically induced coma. She never regained consciousness.
She was moved to a hospice in the city of Duluth, Georgia, a month ago after her condition deteriorated.
Bobbi was the only daughter of Houston and R&B singer Bobby Brown.
Her mother, Whitney Houston, died from a drug overdose in 2012 while sitting in a bathtub at the Beverly Hilton Hotel.
“Bobbi Kristina Brown passed away July 26 2015, surrounded by her family,” Ms Foster said.
“She is finally at peace in the arms of God. We want to again thank everyone for their tremendous amount of love and support during these last few months.”
In January, police said Brown was found face down in a bathtub in the suburban Atlanta home she shared with Nick Gordon, the man she called her husband. A police report described the incident as a “drowning”.
Mr Gordon said at the time she did not appear to be breathing and lacked a pulse before emergency services arrived.
Bobbi was placed in a medically-induced coma and has been breathing with the aid of a ventilator.
TMZ reports that her co-guardians – aunt Pat Houston and dad Bobby – had to make the decision to withdraw medications.
“It was a rare moment of agreement for the Browns and Houstons who had battled about BK’s condition throughout her hospitalisation.”
She will be buried next to her beloved mother whom she was very close to.
Her body will be flown to New Jersey following a funeral service in Atlanta so she can be laid to rest alongside the singer.
Whitney was buried at Fairview Cemetery in Westfield, New Jersey next to her late father, John Russell Houston who died in 2003 following a long battle with diabetes and heart disease.
Bobbi was 18 at the time of her mum’s death and was left devastated. Soon after Whitney’s death, the teenager suffered a hysterical breakdown and was sedated in hospital.
She was latterly treated for severe stress and anxiety. More recently though, she was depressed and was at times suicidal, according to her cousin, Jerod Brown.