I have backed Narottam from day one and I like what you said because I've known it since day one. The guy isn't evil. He isn't conniving. He isn't calculative. He's been hated all his life. Shackled, bound, tortured, hated, forced to become a shadow.
In that time if anyone showed a bit of care for him it was his mother albeit it was more forced because everyone hates Sudha and Narottam so of course the two would bond over that.
But now Anami has arrived and suddenly Narottam is seeing a whole new person.
Vatsalya was a good brother. He cared for Narottam. That much is evident. But he never actually stood up and fought. Yes he refused to go to Banaras without Narottam, but that wasn't really a stand. He knew that everyone would bend to his wish. It wasn't any solace for Narottam.
But Anami is different because no one is bound to listen to her. Everyone has made that much clear. And she's made it clear that she's hear to bring change in the house and find out what really happened to Vatsalya. Once her mission is over, then Lal Mahal can go to hell as far as she cares. That I-don't-give-a-damn-attitude and loud personality (not negative) has won Narottam over because he's finally seeing someone who will ensure that no one touches him when she's around, who will fight for his rights over her own, who will give up anything to side by him. That's what Narottam needed.
I read a comment on the forum yesterday. I don't remember who wrote it, but someone said that when it comes time for Narottam to go against everyone and use Anami, he will see sense and love and hopefully go over to the right side. I agree. The day Narottam's truth is revealed he will have to choose Sudha or Anami. And given the way both are treating him, I can see him choosing Anami. At the same time, he will be broken when he realizes what Sudha really is because she's his mother and the closest he's seen to love.