I think the reason why Sumitra has been able to get away with her rude behavior is that Dadisa has mellowed down so much. Earlier, one could not even fathom Sumitra shouting in front od dadisa even on her own kids...especially in situations which were not right according to Dadisa...but now she has been doing this so often...
I think she was nice earlier to anandi because she could understand the pain of being a woman...but now when she has got a better position in the family, she seems to have become arrogant towards weaker women...such a hypocrite...her own daughter carrying a baby was married to a virgin boy...his son has already married and destroyed the life of two women(one being so dear to her)...and she still cannot be emphatic to Ganga...
It better that Dadisa picks up her danda again on Sumitra...that was better...Dadisa has got her own independent thinking...she is not like Sumitra...who can be influenced so easily.