@Violetta tbh in lillians flashback of the og story. It seems that all his children are alive. I speculate is that the duke doesn't want any of his children to die. But smthing is forcing him to maintain tradition. But I could also be wrong. He might also be kind of father who would care if you're alive but not care when you die. Indifferent but not totally type of person.
Green flags are the only way to go.