Bobbi Kristina dating 'adopted' brother LOS ANGELES, March 15 (UPI) -- Bobbi Kristina Brown's maternal grandmother, Cissy Houston, is upset the teen is romantically involved with a man her mother, Whitney, helped raise, TMZ said. Brown has been making headlines since Whitney Houston died in a Los Angeles hotel room last month at age 48. The singer's only child with ex-husband Bobby Brown was hospitalized twice for anxiety after Houston died of a possible lethal combination of alcohol and prescription drugs. Rumors immediately began swirling Bobbi Kristina has substance abuse problems of her own and her family wants her to check into rehab. It was later revealed the 19-year-old aspiring singer and actress is the sole heir of her mother's estate. Now her romantic life is in the news. TMZ quoted a friend of Cissy Houston as saying the Houston family matriarch was furious after photos surfaced online showing Bobbi Kristina kissing 22-year-old Nick Gordon, a non-blood relative Whitney regarded as an adopted son and who lived at the Houston family home in Atlanta since he was 12. "What they're doing is incestuous," Cissy's friend told TMZ Cissy said about Bobbi Kristina's relationship with Gordon. The insider also said Cissy is concerned Gordon will take advantage of her granddaughter because she is vulnerable right now. TMZ said Cissy has asked the Whitney Houston estate to take legal steps to have Gordon evicted from the Houston home.