A source close to the Kardashian family tells ET, "Lamar is conscious and was able to say hi to Khloe, but his condition remains guarded."
Lamar gained consciousness on Friday morning. According to another source close to the 35-year-old athlete, he woke up, pulled the ventilator tube out of his mouth, and briefly said, "Morning -- hi, baby," to his estranged wife, Khloe Kardashian.
The basketball star has been in and out of sleep and is reportedly “not out of the woods.” Still in critical condition, Lamar is sedated, back on the ventilator and requiring a breathing mask.
“It is too soon to tell,” the source tells ET on if Lamar’s condition is improving.
Khloe has not left her ex's bedside since arriving at Sunrise Hospital in Las Vegas on Tuesday night and is still wearing the same clothes she arrived in.
On Tuesday, Khloe was joined by her mother, Kris Jenner, and older sister, Kim Kardashian, but both left on Thursday because Kim had a pregnancy check-up scheduled in Los Angeles. Kylie Jenner and Kourtney Kardashian also took a trip to Vegas and have since returned to L.A., but Kris, Kim, Kylie and Kendall Jenner will all return to Nevada on Saturday.
Kim was originally scheduled to have a baby shower in anticipation of her second child, a son with husband Kanye West, on Saturday, but the celebration was cancelled amid Lamar's hospitalization.
Lamar was found unresponsive at the Love Ranch -- a legal brothel in Crystal, Nevada, where he had reportedly been staying for four days -- on Tuesday. He was placed in a medically induced coma on Wednesday after suffering a heart attack and organ failure, and later on dialysis.
Prior to waking up from the coma, a source told ET that there had been encouraging moments, including Lamar briefly fluttering his eyes and, at one point, Kim believed he squeezed her hand.
"They have tried so hard to help Lamar with his issues and it breaks their hearts that he could lose this battle," a source close to the family told ET on Wednesday. "The entire family is pulling for Lamar to make it through this."