Who knows
I think they would have wanted Eugene and Hari to be truly happy
And in those times it is not that immoral as it is now
I'm not gonna say that I'm right cuz kids are sensitive. In my opinion, I think that the parents would be really upset and send Eugene away for some time so that their secret no longer continues. Maybe they wouldn't but will have a discussion on how they can't be together because they are siblings if not by blood then by them (the parents) being the Hari's new family. By LAW they would be seen as siblings by everyone who is introduced/ knows the family. In those times depending on the circumstances it could also be seen as scandalous and Hari can be seen as a seducer since her new brother caught feelings for her. Everyone is entitled to their own opinion and to enjoy the story but shouldn't be surprised when another person doesn't share the same opinion all love <333
Yk if the parents had never died, this relationship wouldn't be supported let that stick in your head