Rob Kardashian
Rob Kardashian arrives at the opening of the Kardashian Khaos store in Las Vegas in 2011. Reuters

Rob Kardashian's family is said to be extremely concerned for the 28-year-old following his latest Instagram post which slammed his sister "Keeping Up with the Kardashians" star Kim Kardashian. A source recently told People they strongly believe he needs to seek help dealing with his various issues, which in recent years have included somewhat public battles with anxiety, depression and weight gain.

Rob's sister Khloe Kardashian recently came forward, revealing that her brother "has kind of a social anxiety" and is "definitely not at his happiest place." While some of these struggles have played out in front of E!'s cameras on "Keeping up with the Kardashians," the youngest of the Kardashian children has done his best to stay out of the public eye, something sources say has been no easy task.

"It's really hard for him that his sisters are so public and he looks like the shut-in," a source told People.

Rob has come under fire multiple times in the last few months due to his weight gain, as well as rumors suggesting he may have had a substance abuse issue. Because of the constant scrutiny, Rob has chosen to withdraw from both the public eye and his family. As was discussed on a previous season of "KUWTK," the youngest of the Kardashian children spends significantly less time with his family, avoiding family vacations as well as other events. Sources are now saying that Rob's issues are deeper rooted than just weight gain.

"The attitude has always been that when Rob gets his act together, starts working out and loses weight, everything will be good and he will be happy," a source close to the show's production recently told People. "But behind the weight gain is this very unhealthy mental state that he keeps struggling with."

The source adds that his family has tried many times to help him, but he has not been receptive. Still, they continue to push for him to get well, trying everything in their power. "He is very against therapy and any kind of rehab," the source said. "But his family will continue to push for him to get help until he does."

Still, his opposition has not stopped them from trying. Hollywood Life reports that momager Kris Jenner recently called the family together for a family meeting to discuss "how to best handle" the "situation" involving Rob.

"That's how Kris handles a family crisis' with a big family meeting. She wants everyone there to make sure they are on the same page. Part of the meeting will be to brainstorm ways to help Rob, but another part will definitely be so Kris can make sure everyone is on message," the source said.

The Kardashian family's concern has grown after Rob's recent social media outburst. He shared a photo on Instagram, the only photo on his account at the moment, comparing Kim to Amy Dunn, the villain from last year's "Gone Girl." While one source has brushed off the post, saying that's just Rob's sense of humor, others say it is a cry for help.

"Rob has become progressively more and more anti-social. He always plays down his issues but it's time something has to change. Rob has a dark sense of humor and tries to play off his outbursts like they are a joke, but this latest post definitely got everyone's attention. They just can't afford to ignore him anymore," Hollywood Life's source added.

As we previously reported, it had been widely believed that Kris was furious at her son and demanded he apologize to Kim for the attack, in which he reportedly refused. Now, Hollywood Life says stepfather Bruce Jenner spoke to Rob, telling him "that he better get his act together."

The Kardashian family has not commented on the situation.