Sure, Haylie just welcomed her daughter Ryan three months ago. And yes, Hilary's son Luca is reaching toddler status at three years old.
But in a short amount of time, both sisters have witnessed a bond that is only going to get stronger in time.
"He can be really sweet with her," Hilary gushed to E! News when describing her son's relationship with Ryan. "She was crying the other day and he was like, ‘Why is she crying mom? Why is she crying?'"