Bhala hua toh she will force shaadi of abhir and kiara and tabhi koi kaand hoga during this forced shaadi or will tell that mein paalungi ki ke bacche ko as mere bhai ka ansh hai and all crap
The second possibility seems to be more likely to happen. I feel like beginning of the end for Gen 4 has started with this kiara pregnancy track. Abhir ko udayenge at the end moment and due to this Abhira will step up in to give parvarish/legal name to Abhir kiara kid as you said because the baby is her bhai ka ansh logic.

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