"That was almost a relief, because then he can take all the steps," Jenner, 60, told Extra of what's next for her son. "It was like a godsend, so it's all good."
Kardashian, 28, was hospitalized shortly after Christmas for stomach problems, with Jenner confirming last week he had been diagnosed with diabetes.
Kardashian has shied away from the public eye for almost two years after significant weight gain and battling depression.
Jenner said what happens next are up to her son.
"It's one thing to say, 'Oh, I'm going to get on the healthy path,' but then you really need to get on the healthy path," Jenner said. "Rob has been to that happy place before in his life."
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Jenner also opened up to Extra about Scott Disick, who split from her daughter Kourtney Kardashian and completed a month-long stay in rehab late last year.
"Scott will always be part of our family and we love him very, very much. And he's the father of my grandchildren and he and I were together a couple days ago having a great time," Jenner said. "And he's doing well and will always be a part of our family."
For more from Jenner and her family, Keeping up with the Kardashians is new Sunday (9 p.m. ET) on E!