I have a feeling that the marriage will be stopped and the elder brother will marry soni after realising the grrom is the old guy. After the marriage, the younger brother will come home and meet his new sis-in-law and discover his love married to his brother.
I don't know why I think this but it looks like that's what's gonna happen, i.e. soni said that she wants to marry someone like her elder bro-in-law and her love leaving for business trip. I think there is an hindi movie with meenaxshi sheshadri where she's in love with 1 brother and he goes away for some business and comes back and see his love married to his brother. In that film, the elder brother didn't know that his brother loved his wife til the end. I wonder what will happen to this situation and how it will get resolved.
Munira