Rob Kardashian is not in the mood to celebrate fatherhood

Rob Kardashian is not a happy father-to-be!

In a sneak peek at Sunday’s season finale of Keeping Up with the Kardashians, Kim, Khloé and Kourtney are sitting around the kitchen table discussing Rob’s upcoming baby shower, which they’re all throwing for him.

Kim reveals to her sisters that there may be issues with Rob, 29, attending because he and his fiancée Blac Chyna are “fighting again.”

“What’s the fighting about?” asks Khloé, 32.

“I don’t know. I mean she texts him crazy things, he texts her crazy things all night long,” Kim tells them. “He just doesn’t want to go to the shower.”

“We have this shower planned for tomorrow for Rob and Chyna, but now they get into this big fight and we don’t know what’s going on,” the 36-year-old says in an interview.

Kim begins to read a text from Rob and says, “He doesn’t want to celebrate a shower because this pregnancy has been really bad for him and really awful for him.”

Khloé starts to get upset and says, “We should try and get him to come for mom. If it’s for nobody else, it should be for her. She does so much for him.”

Since filming, Rob has taken to fatherhood like a natural after welcoming his daughter Dream Renée Kardashian with Chyna, 28, on Nov. 10.

“Rob is getting used to taking care of his daughter. He was a little nervous at first, because she’s so tiny,” a source recently told PEOPLE of the new father. “He seems very eager to learn how to care for her. He’s changing diapers and very hands-on. He keeps saying that Dream is the most beautiful baby he has ever seen!”

The Keeping Up with the Kardashians season finale airs Sunday at 9 p.m. ET on E!