Rob Kardashian and his sisters are beefin'; what else is new?      

Khloe, Kim, Kylie and Kourtney planned a shower for their brother, who is expecting a baby with on again, off again fiance Blac Chyna, and at the last minute he didn't show up! 

At first sources told US Weekly he bailed after hearing the party would be filmed for their show, "Keeping up with the Kardashians," so he was like, "f—k that."  

Or maybe they're just too cool for tradition. Apparently the couple plan to throw a "co-ed, gender neutral" baby shower on Oct. 2, which they'll film for their own show, "Rob and Chyna." A source told US Weekly that the sisters will not be in attendance, as they're not tight with Chyna's friends, like Amber Rose. 

Back on Monday, Rob tweeted out Kylie's phone number followed by a bunch of laugh-crying emojis. He has since retweeted it, adding what may or may not be the real reason he's pissed: "Didn't invite the Mother of my child to a baby shower you were all trying to throw for me. You all must have lost your damn minds."

But wait, yesterday TMZ reported that she and Rob have actually been broken up for months, and that's why Chyna wasn't invited. Sounds like they were just trying to be supportive sisters. 

His family is worried about his physical health, in addition to the emotional toll of this unhealthy relationship—since getting together with Chyna, he's gained back the 50 pounds he lost only a few months back. 

So. Much. Drama.