For the past couple of episodes, it's been easy enough to say Soha's behaviour is a result of her being threatened by Ayush taking her place in the household. That being said, nobody ever seems to correct her bad behaviour.
Today during the whole icecream scenario, she straight up laughs at Ayush's face and taunts him when his icecream falls- that too in front of her mother and grandmother and nobody reprimanded her! Any of our parents would've immediately shut that down with "aise baat karte hai? Sorry bolo". Personally, I wouldn't even have the guts to pull that shit in front of my mother.