Khloe Kardashian Worries Rob 'Will Go Into Hiding Again' After Arguing With Blac Chyna

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Khloe Kardashian is expressing her concern for Rob Kardashian after hearing that her brother has been arguing with his pregnant fiancee, Blac Chyna.

In a new promo for Keeping Up With the Kardashians, Khloe inquires while chatting with her sister, Kim Kardashian West, and mother, Kris Jenner, about Rob's well-being. "They're still not talking to each other?" she asks. "How long is that gonna go on for?"

WATCH: Pregnant Blac Chyna Poses Nude on the Cover of Paper Magazine -- Just Like Kim Kardashian!

"I talked to Chyna and it scared me because it was everything that we had experienced with him, she was experiencing the same thing," Kris shares. "So, she wrote me last night and she said, 'Can I see you tomorrow? I just really need to talk to you. Rob won't talk to me.'"

Kris adds that she's uncertain of what Rob and Chyna are fighting about, which leads Kim to ask, "Is he ever gonna see his kid though, or is she gonna take it?"

WATCH: Rob Kardashian Criticizes Family for Not Embracing His Relationship With Blac Chyna -- 'You All Aren’t Welcoming'

Clearly worried, Khloe adds, "You really think they're over? He seems like when I talked to him he was very much in love with her. Am I missing something? How long have they not been speaking for?"

In her on-camera interview, Khloe reveals how concerned she is that Rob will return to his reclusive ways. "I know when my brother hurts how badly he does hurt," she says. "The more they're fighting and the longer things are bothering him, the more depressed he gets. He'll go into hiding again, go missing. I don't want Rob to live that life anymore."

WATCH: Kourtney Kardashian Sympathizes With Rob After Huge Fight Over Blac Chyna -- 'It Took Years for People to Like Scott'

Earlier this month, a source close to Rob told ET that he was "just going through one of his mood swings, which is common for him," but was still committed to filming his reality show with Chyna.

"He goes through his dark periods," the source adds. "He gets depressed and doesn't want to really do anything, doesn't leave the house. It got better for a bit when he first started dating Chyna, but he's in a rut now. He'll snap out of it."

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