Khloé Kardashian has been keeping a constant vigil at the hospital bedside of Lamar Odom since his Oct. 13 hospitalization, and at home, there is another man in her life who needs help.
"Rob is such a great guy," Khloé tells PEOPLE exclusively of younger brother Rob, 28, who has been out of the public eye – and away from the cameras – for nearly 18 months. "He's charming, charismatic, everything. That's what's so infuriating. I'm like, 'Where is your will to live life? Let's be around people!' "
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"I've been working on my patience," she says. "I've been really trying. But I have my moments and I do snap. I've offered to get a chef, I'm like, 'What's your excuse?' But it's not just that. I can't win life for Rob. I have to wait until [he's] ready to do it for himself."
For much more from Khloe, including an exclusive interview and book excerpt in which she talks about the sad demise of her marriage, her body image struggles and the impact Lamar's problems have had on her brother Rob, pick up the new issue of People, on newsstands Friday
The Keeping up with the Kardashians star says her has struggled since her split from Odom. "My dad died when Rob was 16," she explains. "Rob doesn't have a father figure in his life. When [our stepdad] Bruce [now Caitlyn Jenner] was around, he was great, but he was going through his own things that none of us understood at the time. Lamar was [Rob's father figure]. Once Lamar left – and it's not Lamar's fault at all – I think Rob didn't know where to go. He was like, 'I don't have guidance anymore.' "
Now, Khloé says she just hopes Rob will find a way to get healthy – and happy – soon. "It's sad, because he's only wasting his life more and more," she says. "But he has to figure it out for himself. And he has so many people who want to help him."
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Kardashian's new book, Strong Looks Better Naked, hits stands Nov. 3.