Premise: Dad is a 1989 American comedy-drama film written and directed by Gary David Goldberg and starring Jack Lemmon, Ted Danson, Olympia Dukakis, Kathy Baker, Kevin Spacey and Ethan Hawke. It is based on William Wharton's novel of the same name. The original music score was composed by James Horner. The film was produced by Amblin Entertainment and distributed by Universal Pictures.
Hypothesis: William Wharton wrote the novel Dad in the 1980s.