It can't be easy to be engaged to your ex's current girlfriend's brother (phew!) — or to be dating your brother's fiancée's ex (got that?). But Blac Chyna and Kylie Jenner seem to have made peace their complicated relationship.In April, Kylie snapchatted that she and Chyna were "best friends" despite the not-so-nice things they've said about each other in the past. Chyna and Jenner also managed to stay cool when running into each other at Khloé Kardashian's birthday.They may have an awkward past, but it looks like they've put it behind them, at least enough to do what's best for their family. Maybe Kylie will also help out with the baby Rob and Blac have on the way.