The 36-year-old reality star and 32-year-old club promoter celebrated the holiday with Kardashian's family Thursday, and appear to have spent time together again Saturday.
Kardashian and Disick were together nine years before splitting in July. The former couple were spotted together for the first time since the breakup Nov. 13, and were seen again at lunch in Calabasas, Calif., on Wednesday.
"He's in a very healthy place and he's being a lot more authentic than before," a source told People of Disick this month. "He used to always talk about 'taking responsibility,' but now it seems like he's actually taking responsibility by trying to spend time with his kids."
Disick has struggled with substance abuse for years, and left rehab again Nov. 11. He and Kardashian share 5-year-old son Mason, 3-year-old daughter Penelope and 11-month-old son Reign, and have starred on E! series Keeping Up with the Kardashians since 2007.