They split almost two years ago, while their divorce was finalised in July.
But it's clear that the lives of Khloe Kardashian and her extended family remain deeply entwined with that of Lamar Odom, who this evening remains in a critical condition in a Las Vegas hospital.
His chances of survival have been described as "50/50".
The former professional basketball player was found unconscious after spending four-days in a Nevada brothel.
Today his former sister-in-law Kendall Jenner, 19, tweeted her support from Asia, where she is currently working. Keeping her message short, she simply wrote: "please don't go".
Rob Kardashian, who has been largely reclusive in recent times, as well as Scott Disick, 32, the controversial former partner of Kourtney Kardashian, have also rushed to be by Mr Odom's side.
In particular, 28-year-old Rob once had a close bond with New York-native Lamar. Indeed, he lived with him and Khloe for much of their four-year long marriage.
Meanwhile Khloe, 31, is said to be 'inconsolable' and is blaming herself for the incident.
"Family and friends are extremely concerned for Lamar," his publicist Eve Sarkisyan told Us Weekly in a statement.
Lamar, 35, had been drinking at the Love Ranch, a legal brothel, when he was found unresponsive in a bedroom. He was also reportedly taking a herbal Viagra alternative.
Now TMZ, which broke the story this morning, is furthermore claming that the 6ft 10in athlete had a large amount of cocaine and opiates in his system.
"Doctors have told people close to Lamar the fluid they found in his lungs was the result of crack cocaine use," it adds. It later reported that he is suffering from kidney failure and has had "multiple strokes".
And a further source reportedly based inside the Sunrise Hospital in Las Vegas where he is receiving treatment, also told E! News that "drugs were found in his system," and that doctors are treating the incident as an "overdose."
"Likely there's brain damage," the source went on to say. "Virtually every drug imaginable was found in his system."
Lamar appears to have suffered an "ischemic stroke," which is caused by a clot preventing blood flow to the brain; it is often associated with a cocaine overdose. The E! source adds that Lamar "had been partying since Friday".
"He was doing crack cocaine all weekend and he choked on his mucous," the insider explains.
"They're now having to fix all the damage it has done."
Mr Odom has two teenage children from a previous relationship. A third child, Jayden, died aged six months in his sleep in June 2006 in New York.