In this article, they did not mention main reason - why Kabir should accept all the blame? To save Nisha - if she didn't get blood at right time, she will be fighting with death. No one saw -how much Kabir sacrificed for his love? He landed up himself in a big mess...only to save Nisha.
He knew - once Nisha is OK -they will fight with any situations.
I don't see Kabir as a 'drama bahu' - I would do the same if I was in his place - while Sumit was giving blood, ofcourse I will forward that audio to all of the cousins with strict instructions - not to take any action until Nisha is alright and at home.