Rob Kardashian is upset with his elder sister Khloe Kardashian for making him “believe” that she was getting back together with her estranged husband Lamar Odom, Radar Online reported Wednesday. According to the report, Khloe was dating her ex-boyfriend James Harden following a brief breakup with him after Odom’s hospitalization.

“Rob hates how she’s strung Lamar along and believes that’s why he went even further off the rails than he would have had she just set him free,” a source told Radar Online. “She [Khloe] led him to believe there was a chance of a reunion for so long that he put everyone on hold and had to sit there while she was wined and dined by all these other guys,” the insider added.

The entertainment website added that Khloe and Harden got back together after it appeared that the 31-year-old was trying to reunite with Odom. “Rob’s disgusted with her and tore into her in a big way for going on a date with James while Lamar was in hospital,” the source said.

Meanwhile, Khloe, who announced Wednesday that she was healing from staph infection she contracted in a hospital where Odom was treated in, tweeted Thursday that 2015 was the worst year for her so far.

Odom is hospitalized after being found unconscious at a Nevada brothel in October. The 36-year-old was making “some progress” but was unable to walk by himself and struggles to communicate. "Lamar won't likely leave the hospital for a long time," a source reportedly said. "And when he does, he will need full time care. He can't take care of himself."