Sugni looks at him in the hopes he will defend her against his nephew, that he will say something but he doesn't say anything. In fact, he remains silent, loosens his hold on his nephew and goes so far to looking away from Sugni - he looks ashamed and embarrassed. He cannot even look her in the eye. Now, this scene I found very strange because if TVS really did not hold such views, he would have said something to his nephew for calling Sugni these names AND his nephew would not have made such comments.
Watch the scene...
http://www.dailymotion.com/video/xqpg6e_phir-subah-hogi-episode-16-9th-may-2012-pt1_shortfilms?ralg=behavior-meta2#from=playrelon-2
(Episode 16, May 9th Part 1)
http://www.india-forums.com/forum_posts.asp?TID=2970689 - for the episodes..
Here is my take...TVS is calm but calculating man...he might not be married and he might be sincerely in love with Sugni deep inside...but he might not be open to the idea of making her his wife...he might really see her as someone whom he can love but never marry. Perhaps he even sees her as someone whom he can use, dominate etc. This all supports what the mother has been saying to Sugni along.
Now, take out the storyline of Aditya and Sugni love story.(these scenes are probably fillers and perhaps Aditya will be the person to unite them rather than become the one who falls in love with her or VV)
But what does a young girl do when she has fallen for a guy who does not wish to marry her but will make her his mistress? Will he force (emotionally) her into that role or emotionally will she give in?
Check out the scene and let me know, does it not strike you as odd when he turns away when Aditya makes those comments?