Hi friends,
I dont think Renuka is a negetive character...she is aware of the changes happening in Navya...she is also aware about Navya's friendship with Anant ...eventhough girl-boy friendhip is not appriciated in Navya's family Renuka hide about Navya- Anant's friendship because she dont want to upset the parents...so, from Renuka's side it is quite natural not to support her sister as she is doubtful about Navya...
Renuka was also bought up the same way like Navya...got married and now a mother at a younger age...
I think when the story moves on with Renuka unhappy with her own in marital life, Renuka will be the first one to support her little sis...
Smi