So far, there has been no statement issued by the producers on the film's plans, as I imagine they're all suffering from a mixture of shock, grief, and panic. The project, which also includes the likes of Christopher Plummer, Lily Cole, and Tom Waits, focuses on "the story of an ancient traveling show which arrives in modern London with a magical mirror that can transport its audience into fantastical realms of the imagination."
Between this and the Don Quixote turmoil, I would not want to be in Gilliam's shoes.
But I do want to leave you with this sad, yet touching, quote that Variety posted from Gilliam, which he said last month during an interview: "Heath is extraordinary. He's just so good, and he's going to be a film director. He's watching everything, and he's going to be a much better director than I will ever be." (Ledger had been planning his directorial debut with The Queen's Gambit.)
UPDATE: According to US Weekly, the production was shut down.