The Kardashian's are reportedly at the hospital with Lamar, and have each been sharing their own messages for him.
Click through the gallery to see what they've said.
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Kourtney Kardashian captioned this pic, "Believing in the power of prayer for this beautiful soul."
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Rob Kardashian captioned this pic, "Praying nonstop for my Brother !!"
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Kylie Jenner captioned this pic, "Let's dance again together soon. Prayers up for Lamar please."
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Kris Jenner captioned this pic, "Please pray for Lamar #ourfighter."
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Kendall Jenner tweeted, "Please don't go."
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Khloé Kardashian
"The past week has been incredibly difficult," the 31-year-old writes in a message on her website. "I am so thankful to family, friends and fans, who have sent nothing but prayers and well wishes to Lamar."
She continued, "I also want to take a moment to thank everyone at Sunrise Hospital, including the amazing doctors and nurses for their kindness and diligent work. Under their amazing care, incredible strides have been made."
"You can never be prepared for an experience like this, but without the outpouring of love and endless prayers that Lamar has received and the strength I was given from my loved ones, it would be difficult to endure," she ended the note. "Thank you for your continued support. God is great!!!"