The film is originally from Boswell's acclaimed first novel, Crooked Hearts. The family Boswell created in the book becomes one of the most memorable one in recent American literature - an eccentric clan that throws parties to celebrate its failures, that both nurtures and suffocates its members, whose interactions define the term "dysfunctional" but nevertheless have a haunting universal resonance. If you have also another story in Boswell's collection, the Dancing in the Movies, you may trace it back to Crooked Hearts.
Hope you enjoy the movie, and read the novel if you'd like.