Khloé Kardashian advised her sisters not to publicly support Rob Kardashian after his surprise engagement to Blac Chyna

By Lindsay Kimble
Updated June 24, 2016 12:00 PM

Khloé Kardashian was initially not on board with her brother Rob Kardashian‘s engagement to Blac Chyna – and she didn’t want her sisters to be, either.

In a new clip from Sunday’s episode of Keeping Up with the Kardashians, Khloé and siblings Kylie Jenner, Kim Kardashian West and Kourtney Kardashian read about their brother’s marriage plans on TMZ while getting primped in a makeshift glam room during their Vail, Colorado, vacation.

“Rob Kardashian: my family didn’t know jack about my engagement,” Kim reads as her sisters listen. When the 35-year-old comes to the part of the article that notes the famous family has yet to publicly comment on Rob’s news, Khloé whispers, “Why would we congratulate him.”

She then advises, “And no one should congratulate them, that’s so desperate and fake of whoever does first, because I know someone’s gonna break.”

Kardashian proposed to fiancée Blac Chyna in April after opting not to join the rest of the Kar-Jenner gang on the ski trip. The 29-year-old, who is now expecting his first child with Blac Chyna, opted not to clue his family in ahead of popping the question.

“In reality, none of us really care we just want Rob to be able to tell us when he’s going to do something big like this,” Kylie, 18, says in an interview from the clip.

Related Video: Rob Kardashian Says ‘Everything Is Exciting’ About Blac Chyna’s Pregnancy But Wants to Keep It ‘Private as Can Be’

During a previous episode of the reality show, the siblings found out about Rob’s big news – and reacted negatively. “That’s so f—ed up,” remarked Khloé.

Kourtney, however, came to her brother’s defense, charging, “Maybe he thinks that you guys are judgmental because clearly you are.”

Things have since changed post-filming.

An insider previously told PEOPLE, that the family has now come around to Rob’s romance, acknowledging that Chyna has had a positive impact on the dad-to-be’s life.

“They feel like Chyna saved him,” the insider said. “The [Kardashian sisters] have gotten over their issues with Chyna now. They’ve welcomed her in.”

Keeping Up with the Kardashians airs Sundays (9 p.m. ET) on E!