Khloé Kardashian may have feuded with Blac Chyna in the past, but that doesn't mean she won't stand up for her. The Strong Looks Better Naked author, 32, bashes her brother, Rob Kardashian, for not being there for the pregnant model in a preview for the Sunday, October 30, episode of Keeping Up With the Kardashians.

Khloé lashes out against the dad-to-be, 29, during a chat with sisters Kim and Kourtney Kardashian. "We can't act like what he's doing isn't wrong. If this was any man that we were with, we would be pissed," she says in the clip. "He hasn't spoken to her in days."

Kourtney, 37, seems unaware of the situation. Khloé, meanwhile, interjects — and doesn't hold back.

"It's crazy how he's acting. It's f--ked up," she says.

In a confessional, she adds: "Rob is going to be a dad, and he has a family to answer to. I feel like now more than ever Rob can't handle things the way he once did. He has to deal with his problems. He can't just run away and ignore them."

Kim agrees. "Would you be happy with Kanye [West] if he disappeared for five days and never reached out to you?" Khloé asks.

"No," the Selfish scribe, 36, replies. "I'd die."

Keeping Up With the Kardashians airs on E! Sundays at 9 p.m. ET.

Watch the sneak peek in the video above!

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