Ya helping Aarohi get in to a loveless marriage is downright stupid decision in her part, but she knows how stubborn Aarohi is I think she's simply getting out of the way. If you noticed Akshara is just trying to stay away from Aarohi's bad decisions(she refused to go with aarohi to select the rings) because she knows she would be blamed if literally anything goes wrong, blaming Akshu for things is like second nature to Aarohi.
I think responding to Abhi(blushing, smiling) is something she's doing subconsciously. As for why she's not staying away, she's mad at Abhimanyu for agreeing to marry Aarohi. It's her way of showing its your mess learn to deal with it and she's a family oriented person, she can't stay away from her sister and her life.
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