Actually I dont know if anyone said this yet
but
I at first thought he was chachiji's son but then when she caught him she acted as if she didnt really know him
so now i think the Abhi is telling the truth
he is Manoobhabi's son but completely went on his father and his bad behavior
There really is nothing that points out he is not Manno bhabi's son
Not to put a damper on anyones theory but why would he be hired
Why would Manno's ex-husband want revenge after so many years
and who really is Manno's enemy except for maybe Kaveri but she has her own problems and is always after the happiness of Saloni and taking away everyone else khushi. SHe also doesnt seem likely
SO you know Im out of theories and I believe he is the real Abhi but has his fathers Bad blood so he himself is bad