Houston -- who was married to Brown for 15 years -- died in 2012 at the age of 48 after she was found unresponsive in a bathtub at the Beverly Hilton. Three years later, Bobbi Kristina died six months after she was found unresponsive in a bathtub in her Georgia home.
"The hardest thing I had to do in my life was tell my daughter to let go," Brown tells Roberts as he breaks down in tears. "My baby's gone. I thank God I'm still here."
A day after Bobbi Kristina's death, the 47-year-old singer released a statement to ET about his beloved daughter. "Krissy was and is an angel. I am completely numb at this time," he said at the time. "My family must find a way to live with her in spirit and honor her memory. Our loss is unimaginable."
In an interview with Dr. Phil last April, Bobbi Kristina's boyfriend, Nick Gordon, was candid about discovering his girlfriend unconscious in a bathtub, and how similar the situation was to the death of her mother three years earlier.
"It was literally a nightmare all over again," Gordon, 20, said.
ET's Kevin Frazier spoke with Dr. Phil about Gordon's state of mind during their talk, and if he thought Gordon's recent stint in rehab was beneficial. Here's what the talk show host had to say: