Sarah's biological dad is a bit of a d*ck
He doesn't see her for 30 years and makes no effort to contact her ... fine, I guess I can live with that. I guess he had his reasons.
What rubbed me the wrong way though is when it came to making the documentary / film. He wanted to do it HIS way only and told Sarah that getting other points of view wouldn't make for a good film.
He kept describing his relationship with Sarah's mom as 'so passionate' almost to the point where no one else could possibly understand. While I have no doubt that he loved her, I'm not so sure it was as reciprocated as he thinks. I think Sarah's sister probably had it right when she said that her mother's true love was for Michael, but Michael didn't love her the way the biological father did.
It raises an interesting point - would you rather be with someone YOU love, but that person doesn't quite love you or live the way you want ... or with someone who loves you with everything they have, but you don't quite feel the same way?
Anyway, that's the impression I got about the biological dad.