Responses
The duke's just finally managed to prove he does NOT discriminate between his non-blood-related kids and Ludville (the only bio kid that he knew he had, up till now). Favoring new girl would make no sense because it'd be like going backwards on all that, "back to square one"... disregarding all his character development.
Honestly I don’t think the daughter would pose much of a threat to Camilla. Sure she is the legitimate daughter but Camilla is also the duke’s daughter by law since her mom married him. If talking about parental love, Camilla doesn’t give a shxt anyway ╮( ̄▽ ̄)╭