He filled the position internally, according to People:
As she gets older, Ethan Hawke's daughter Maya Ray is a great help to her father."Maya is about to be 12, so she's getting pretty good with the baby," said Hawke, referring his and wife Ryan Shawhughes's 1½-year-old, Clementine.
Well, this should serve as a warning to all movie stars. Never spoil your help by marrying them.