I'll clear the confusion for people who have confusion regarding the siblings' relationship
..So Khushi's dad was in a relationship with kevin's mom before he met and married khushi's mom but they had already broken up before he met khushi's mom ... Kevin's mom didn't know she was pregnant and by the time she found out khushi's dad had already married khushi's mom and she didn't want to disturb his life.but mr.richards found out and wanted to get divorced from khushi's mom but Kevin's mom didn't want that to happen so she left without saying anything but Mr.Richards still helped her financially so she could bring up kevin properly...by the time khushi's mom found out about kevin and his mom she already had Shyam and Khushi but instead of blaming Mr. Richards she accepted Kevin's mom and kevin as part of family...a few years later Khushi's parents were on the way to the airport with khushi and shyam when they met with the accident and khushi lost a major part of her memory except her name when khushi's parents died Kevin's mom tried to find them and take them in as family but she couldn't trace them anywhere so she told her son kevin to find her and take care of her because she felt that she owed Mr.Richards that much for giving her kevin and to khushi's mom for accepting her and her as part of the family...
I hope this will clear some some the confusion...
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