The 17-year-old "Keeping Up with the Kardashians" star said Kourtney, 36, has the full support of all her sisters, reported Contactmusic.
"Kourt is actually doing great... Everyone's doing good. I'm doing good. We're sisters. We always stick together."
Kourtney, who has three children, Mason, five, Penelope, three, and six-month-old Reign, with Disick, has sought comfort in her sisters Kim Kardashian and Khloe.
The trio were spotted out for dinner earlier this week and out at Malibu Wine Safari, without Kylie or Kendall Jenner.