Responses
I don't think that Jeanette is aware that Claude isn't her father. In the original book Jettie was in the position that Athy is in (pre amnesia of course) so either the story has changed again or there was no purpose for the original story to go into this since Claude and Jettie had their happy end.

So wait, if that is to be Jeanette's dad...wouldn't that make her Athy's cousin instead of her sister? (⊙… )