Duke knows everything because this is not the first time kana is living her life because duke of addis is restarting the world countless times with the help of kana mom and hostility look was because kana mother was the one who curse the duke so he is not able to sleep in his whole life because when kana leave her mother body kanan mom consciousness returns and she thought duke is doing wrong things to her so she cursed her

If i remember correctly there is a kana biological mother potrait and about strange behaviour of raphel because he loves kana and he knows she doesn't have memories yet and he is controlling himself that's why he is avoiding her and soon the divorce arc will start and after the divorce kana younger brother will kidnap her and lock her in a island so no one can find her and in future kana will possess her biological mother body and duke of addis (kana current father) will fall in love with her and she told the duke to protect her when she is born in the future