Bobbi Kristina Brown
Cissy Houston and Bobbi Kristina Brown (R) attend the opening night of "The Houstons: On Our Own" in New York on Oct. 22, 2012. Reuters/Andrew Kelly

Days after Bobbi Kristina Brown’s father Bobby Brown filed papers with a Georgia court for the guardianship of the $20 million estate Bobbi Kristina got from her mother Whitney Houston, grandmother Cissy Houston has decided to “fight this to the grave,” Radar Online reported, citing a source. Bobby Brown's move comes soon after Cissy said in a statement that the damage to Bobbi Kristina’s brain was “irreversible.”

“Cissy Houston will fight this to the grave,” a family source said, according to Radar Online, adding: “Since day one, all of the Houstons have been waiting for Bobby to try and get Bobbi Kristina’s money and they knew it was just a matter of time. No one is surprised that he is making a grab for her money.”

According to the will signed by the late Whitney before her death, Cissy, Bobbi Kristina’s uncle Gary Houston and aunt Pat Houston would receive the estate’s responsibility if Bobbi Kristina dies. The 22-year-old was found unresponsive in her bathtub at her Georgia home in January. She was put under a medically induced coma and remained on life support. She was later transferred to a private room at the Dekalb Medical facility in Atlanta. Although Bobbi Kristina is no longer in coma, she still remains unresponsive.

Despite suspicions that Bobby Brown is trying to take control of Bobbi Kristina’s inheritance, a source had told People magazine that he “only wants what’s best for (his daughter).” Bobby Brown also reportedly understands that his daughter may “live in this condition for a lifetime.” The filing for guardianship is also being seen as an indication that he does not believe Bobbi Kristina will wake up, according to reports.

"Bobby is Krissy's father. He only wants what's best for her," a source close to Bobby Brown reportedly said, adding: "This is not about him taking her money -- he has money of his own. This is about making sure that she will have the best care for as long as she needs. … The truth is that he wants to get her the best care she can possibly get, that's all."