I can see the deep feeling of betrayal Dr. Keyes might experience to cut off communication. After all, do you have any doubt the daughter was practising deception by omission? I'm sure in the Keyes household opinions are not valued just because you happen to like them, but because you can argue their merits. If daughter is holding opinions reprehensible to her father's, and refuses to engage father to give him the opportunity to refute those opinions, what is left?
He either cuts her off, or tacitly agrees to accept her proclivities.
How very logical. I can't fault your logic at all, but we're not talking about logic here, but familial relationships. Relationships between humans with feelings, not Vulcans. I love my daughters. There a million and one things my daughters could do that I wouldn't approve of, things that could hurt me, things that could make me angry, things that could dissapoint me, but not much that could make me turn my back on them.
My oldest daughter, the mother of my granddaughter, is 26. She's an adult, and as an adult she really doesn't owe me the opportunity to refute any opinions she holds. Like any adult, she can choose what she wants to put on the table for discussion, and what she doesn't. What a petty, petty man I'd be if I turned my back on her for not seeing things my way.