Debbie Brooks lived next to Brown and Gordon in Roswell, Georgia, and spoke to PEOPLE exclusively about some of her memories of the young couple.
Back in November 2013, Brown and Gordon attended Brooks' Atlanta-area nuptials, and "they were darling," Brooks recalls.
"The day of the wedding, they got there early ... I am getting dressed and ready to go, and she comes in the room and looks at me and says, 'Oh no, no, no – I got to redo your makeup,' " Brooks says of Whitney Houston and Bobby Brown's daughter.
"I said, 'Krissi, I have to be ready in 30 minutes.' She starts working and is talking away. She says, 'Mama, I am going to smoke your eyes.' She did a beautiful job. She smoked my eyes up, and it was beautiful. She kept saying, 'I did my mom's makeup,' and I thought: 'You know what, if she was good enough for Whitney, then she is doing my makeup.' "
Courtesy Sarah Witherington
The neighbor notes that the pair, who called each other husband and wife on social media but never actually married, were "very passionate."
While Gordon, 25, faces a $40 million civil lawsuit which alleges domestic violence and stealing money, Brooks says, "They were very lovey-dovey. I will say that they loved each other very much. They had a very passionate relationship."
"Their relationship was fast and furious. He was her life support; she was his," Brooks adds.
One of Brooks' favorite memories of her late neighbor was a moment of compassion: When her dog died, Brown and Gordon were there to offer a shoulder to cry on.
"They did not leave my side the whole day. I was just sobbing, and Krissi sat with me loving me, hugging me and talking about my dog," Brooks says. "They stayed late into the night ... It was very special. I will always remember that day."
RELATED VIDEO: Nick Gordon Is 'Devastated' over Bobbi Kristina Brown's Death: 'He Really Did Love Her Very Much,' Says a Source
Brown, 22, died Sunday at an Atlanta-area hospice center, almost six months after being found unconscious and unresponsive in her bathtub.
While both sides of the family were present at Brown's wake Friday evening, boyfriend Nick Gordon remains banned from this weekend's services. On Thursday evening, he issued a plea to Brown's father and aunt Pat Houston to allow him to attend Saturday morning's funeral. Gordon has yet to receive a response.
Reporting by ELISSA ROSEN