"It's the truth," Prupas tells PEOPLE. "The goal of the script from the very beginning was to tell the family story of the Kennedys. There's much written evidence of what went on in that family ... They truly were a great family that has a Shakespearian story arc that resulted in many tragedies and many great successes."
And to be true to history, Prupas says the miniseries, which stars Holmes as Jacqueline Kennedy and Greg Kinnear as John F. Kennedy, did not cover up certain blemishes on the family's legacy.
"It is blatantly obvious from many public sources that the family had certain flaws and certain problems. We weren't inventing the wheel," Prupas says of the film's take on the lives of the Kennedy family members. Still, Prupas adds, The Kennedys "is a positive reflection. But we have shown the flaws."
Originally expected to air on the History Channel in the spring, the cable network pulled the miniseries in an announcement on Friday, saying, "While the film is produced and acted with the highest quality, after viewing the final product in its totality, we have concluded this dramatic interpretation is not a fit for the History brand."
Now, Prupas says he's working – with the "active support" of the History Channel – to find a home for the film.
"We don't have an offer in place. We don't have a discussion going on with a specific network. [But] there are several interested in reviewing the material," Prupas tells PEOPLE, adding, "I know the material and I know anybody who's watched this material and the response has been overwhelmingly positive."
But some network executives, like Hallmark Channel's senior vice president of programming Barbara Fisher, tell PEOPLE there is not much interest in the film. "I haven't seen it but I don't think it is the right fit for us," Fisher says.
Richard Pepler, co-president of HBO, is more direct: "Absolutely, unequivocally no, we are not interested."
With additional reporting by SUSAN YOUNG