Arpita- Aryan are very close to each other. So, he doesn't think that she would hesitate to share with him if she is not ready for this rishta.
Regarding Sundar, Aryan is not being classist at all. He didnt disrespect Sundar. He is just ensuring well being of his sister which is not wrong. That thing aside, Aryan believes though Imlie wish well for Arpita, her priority is Sundar.. n he told her also too n he doesn't have any reason ti beilieve otherwise. From the day the alliance has come, He saw how Imlie is insisting on Sundar. As someone mentioned earlier it's not tht Aryan doesn't trust Imlie. On the contrary, he very well knows Imlie is capable of Imliepanti once she decides upon something . He saw that phone call made to Sundar n in function too he noticed what trick she was playing.
So for me he is neither butchered nor out of character.