No, he's working on another book.
4 seconds sound clip from the The Exorcist movie soundboard.
You can hear this line at 01:39:21 in the Blu-ray version of the movie.
Quote context
[...]
- I had a notion he was over in Iraq.
- I think I read he was working on a dig near Nineveh.
- Yeah, you're right Mike, but he's finished.
- He came back three or four months ago. He's at Woodstock now.
- What's he doing there, teaching?
- No, he's working on another book.
- Don't you think he's too old, Tom? How's his health?
- He must be all right. He's still running around digging up tombs.
- Besides, he's had experience. -I didn't know that.
- Ten, 12 years ago, I think, in Africa.
- The exorcism supposedly lasted months. I heard it damn near killed him.
[...]