The host bashing him, constantly putting him down nd constantly hinting them to patchup, varun coming nd hinting about being friends plus his convo with virasim was shown where his mood was off nd upon being probed by rashmi he admitted that its off coz of all the things that happened between him nd sid. He said its affecting his mental peace nd he is suffering from inside whenever he hears the jibs. His frinds advised him to ignore so he did that for his peace of mind. He himself told shukla that "last k thode din bache hai acche se nikalte hai as he is getting it from salmans nd outside feedback that their fights really tend to get very nasty nd he doesnt want that.
He is taking the initiative here to bridge the gap nothing else nd regarding him going to ss with himanshi nd calling him bade bhaiya, we clearly saw how their bond was before the fallout so he just want to include sid in his happiness as saw sid as umar. He was just too happy nd wanted to include sid in it.
Regarding his proposal to himanshi (solely my pov) i think first he was conveyed by himanshi through parag that she is waiting outside for him nd then SK telling him that he is the reason for her breakup, he is tryina give his aasurance to himanshi nd wants to hear about her feelings for him. He is overwhelmed nd struck by magnitude of feelings..it could be looking ott to others but i think he is just trying to be sincere about it.