When his sister, Kim Kardashian West, 34, Tweeted that she's still experiencing pregnancy-related nausea, Rob replied with some assistance:
"I sent u that voice note. It should help," he wrote on Tuesday, in response to Kim's earlier post: "Wait wait wait I thought this nausea thing was supposed to be gone by now!!!! UGHHHHHH."
@KimKardashian I sent u that voice note. It should help
— ROBERT KARDASHIAN (@robkardashian) June 23, 2015"Should I post it? I think people would love to hear the voice notes u send me!" Kim replied.
While the contents of the voice note are a mystery, it seems Khloé Kardashian's ex might have something to do with it.
Rob responded with some soothing lyrics from Montana's song "Hard Work."
"HARD WORK GONE PAY OFF!! I BE HIGH OFF THIS MONEY I DUNNO WHAT THEY BE ON!!"
@KimKardashian HARD WORK GONE PAY OFF I BE HIGH OFF THIS MONEY I DUNNO WHAT THEY BE ON
— ROBERT KARDASHIAN (@robkardashian) June 23, 2015RELATED: Rob Kardashian Is 'Depressed and a Bit Off' Lately: Source
How this message will help her nausea is unclear, but it's still a big step up from his last Tweet to his big sis, when he compared her to that "bitch from Gone Girl.
"He has a funny sense of humor and posts weird things and then deletes them," a source close to the Kardashian family told PEOPLE at the time. "It's just him."
Despite the rare Twitter joke spree, Rob generally prefers to stay out of the limelight. He was last spotted at a hamburger joint in Woodland Hills, California.
"He's still struggling," a source tells PEOPLE of Kardashian's issues with weight and depression.
"[He] just can't get motivated," the source adds. "Everyone is trying to be encouraging, but for the most part he doesn't want to hear what he already knows."
