Yes, Adi has been made to look completely wrong here and definitely made a mistake. But, there may be something more than what is shown so far, which may be revealed later.
Dont think, they can ruin his character once again by making him look so wrong. And if all this is true, then his guilt and fear of loosing her is completely wrong. And very clearly he wanted to save his brother.
Otherwise, how can someone justify that, after Kavya shows him proof and tells him her faith in him that he never hidden anything and he has been so important for her and believes him that he will never do anything wrong with her, he is still hiding from her (who would do something like that, when he himself keep saying Omi was wrong).
Hopefully, there is something more to it than what is shown so far (something more than Malini's swear as well).