Entertainment Tonight ET Online ETOnline.com

"Her behavior, it's just not normal," reveals a concerned Gary Houston of his late sister's (Whitney Houston) daughter, Bobbi Kristina.

Video: Bobbi Kristina Visits Mom's Grave on 'Houstons'

In tonight's episode of Lifetime's The Houstons: On Our Own, Gary confides with close family friend and Whitney's former bodyguard Ray Watson about behavior he deems suspicious.

Imploring the family confidant, Gary asks whether Ray has seen Bobbi Kristina act in a way that might raise worry.

"We got a situation that we need to address when it comes to [Bobbi Kristina]," says Gary. "I don't know what's happening, but something's going on."

Pics: Remembering Whitney Houston

Watch a preview clip of tonight's episode in the player above.