Will he go off the grid? Khloé Kardashian expresses concern that her younger brother, Rob Kardashian, will “go missing” after he had a fight with his pregnant fiancée, Blac Chyna, in a preview for the Sunday, September 4, mid-season finale of Keeping Up With the Kardashians.

The Strong Looks Better Naked author, 32, sits down with momager Kris Jenner and sister Kim Kardashian to discuss Rob’s fractured romance with Chyna, 28, in the clip above.

“They’re still not talking to each other?” Khloé presses Jenner. “How long is that gonna go on for?”

“I don’t know,” the reality TV matriarch, 60, replies. “But I talked to Chyna, and it scared me because it was everything that we had experienced with him, she was experiencing the same thing. 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.’”

Jenner goes on to say that she has yet to discover why the couple isn’t getting along, which prompts Kim, 35, to wonder if the expectant video vixen will allow her little bro to see their baby after she gives birth. As Us Weekly exclusively reported on July 20, the couple will welcome a little girl.

“Is he ever gonna see his kid, though, or is she gonna take it?” the Selfish author asks.

Despite Kim’s query, Khloé doubts that this is the end of Rob and Chyna’s relationship. “You really think they’re over?” she says. “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 a confessional, the former Kocktails With Khloé host explains why she is worried for her once-reclusive sibling. “I know when my brother hurts how badly he does hurt. 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 the video above. Keeping Up With the Kardashians airs on E! Sundays at 9 p.m. ET.

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