Bio Dad-WHO is HE?

I really enjoyed watching this movie. I do quibble with how we the viewers are to *understand* or *judge* the father who raised the(now adult) children. Yeah, after they were grown he proved to be not such a good guy, but other then he having a whistle to wake them up in the morning and apparenlty being irritating in general, was he a Dad of whom they felt close to or had affection for, BEFORE his run off with the young woman?

Without knowing this, the father has been marginalized to a passive and unclear to his motivations position. Are we to think it doesn't matter about biology in regards to who raises us, or not? That Dorona should adopt a child because of this knowledge?

The three children have to absorb the *bio* couple's shenanigans and their need for continual secrecy, and move on. But what about their own memorizes of their own childhood with the man who raised them?

I can handle ambiguity, but I like to know which facts we are to let go.