And I hate how led on Johan is through out the story. Logically his family was the only one from a good house that would accept an adopted daughter for marriage, now because of their new history together they're closer and this is still an option for her future. That means if she's not considering Johan as a partner now then she has no real plans for her future, at all, which makes no sense. It would make more sense if this story was about her time traveling and getting to know her future fiance, Johan. Then she falls in love with him this time around instead of him being someone she didn't know and had to marry for freedom. I don't think it makes sense for her to fall in love with her brother because there's been nothing special about their relationship its just what the author wants.
Eugene took his position as family head and worked on making a safe place for his family well Johan's family took all of them in and raised them comfortably, she could have bonded with him then. Eugene sends her letters? Well Johan talks to her probably almost everyday since they live together. The author hasn't made anything significant about their relationship other than, oh they may have liked each other in the past, but why did they, and still do, like each other in this fist place? They're comfortable around each other? Aren't all siblings, that's a weak reason. Are they just drawn to one another by an unseen force, are they star crossed lovers? Is the authors fetish incest? Just say so and at least make it make sense.