Cissy Houston, Whitney Houston' s mom reacted fiercely to Bobbie Kristina's engagement

Whitney Houston, Nick Gordon, Bobbie Kristina Brown

Rumors are swirling that the late Whitney Houston’s daughter: The 19-year-old was spotted holding hands and kissing Nick Gordon (pictured middle),  who Houston raised from the age of 12. A source confirmed to Us Weekly the two are engaged and living together. The pair grew up as brother and sister, but Gordon was never formally adopted. Whitney Houston's teenage daughter, Bobbi Kristina, has told her grandmother, Cissy Houston, she will marry Nick Gordon, a longtime friend who's known as her 'adopted' brother, even though the matriarch of the family is vehemently opposed to the relationship, reports RadarOnline.com .

Star magazine exclusively reported in this week's issue,  just one month after Whitney's death, Bobbi Kristina, 19, secretly got engaged to Nick, 22, and she's recently been spotted wearing a diamond engagement ring.

Cissy Houston is "absolutely heartsick that Bobbi Kristina has gotten engaged. This reminds her of when Whitney married Bobby Brown, whom Cissy has never approved of. Cissy has conveyed to Krissy how upset she is, and has urged her to have a prolonged engagement. Krissy has told her grandmother that she doesn't need her blessing to marry Nick, and the more Cissy objects to the relationship, well that as we all know will only cement Krissy's decision. It's just a very sad situation. Clearly, Krissy loves Nick, but she has just lost her mother, and her entire world has been turned upside down. Krissy doesn't think she needs to wait, and points to her mom's sudden death as the reason to marry Nick," a source close to the situation tells us.

"Nick proposed to Krissy on March 10, and she said yes," Star reports.  "Krissy said Nick is the only person she trusts in the world. They have a very deep connection," a family insider told Star.

Bobbi Kristina lives with Nick in Whitney's $1.2 million Atlanta townhouse, and they call each other "brother" and "sister," says the source.

Although he was never adopted by Whitney, she took Nick in several years ago after his father went to prison and his mother was unable to care for him.

"Nick took care of Whitney and Kristina," his grandmother Maxine Gordon told Star. "He's always been extremely protective of Kristina."

Bobbi Kristina has had several heated arguments with Cissy about the engagement, and the 19 year old has said "my mother would have approved of me marrying Nick, and I'm going to do it," the source says.