"They are still married, so if something happens to Lamar, Khloé will have to deal with it," the insider says

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brightcove.createExperiences(); Less than eight months have passed since Lamar Odom‘s near-fatal overdose – and now the Kardashians are worried the former NBA star might be taking another turn for the worse.

Though he’s made incredible headway in his recovery since being found unconscious – reportedly with cocaine and opiates in his system – at a Nevada brothel last October, in recent weeks Odom has been spotted drinking more than once and a source tells PEOPLE he is “a sad mess.”

According to the insider, his friends allegedly “found a drug pipe at his house.”

“When he was first drinking again, some said he was just getting back to normal – clearly this was just a gateway back to his destructive behavior,” continues the source, who says Odom “is an addict and should never have been drinking again.”

Meanwhile, while she’s moving forward with their divorce, Odom remains legally wed to Khloé Kardashian, 31, who has been a major source of emotional and financial support for her estranged husband in the months since his overdose.

“They are still married, so if something happens to Lamar, Khloé will have to deal with it,” says the source.

A different source told PEOPLE last month there had been talks about rehab, but the insider maintains, “Lamar doesn’t want to hear about it.”

“It’s unbelievable that Lamar can’t just admit that he has a problem and go to rehab,” continues the source. “It’s very unfair to Khloé.”

And according to the source, Kardashian and her family are worried about what might happen next.

“His body is not back to normal and it never will be,” says the source. “There is a fear that he will again have an overdose.”

In a sad coincidence, in a recently released sneak peek at this week’s episode of Keeping Up with the Kardashians, Odom opens up about what him relapsing might mean for his estranged wife.

“I can’t really take the risk,” Odom says to Scott Disick in the clip. “I can’t do that to that girl again.”

Keeping Up with the Kardashians airs Sundays (9 p.m. ET) on E!