Yes, he may love his brother but he needs to remember that he is married now and that he has responsibility towards Paridhi as well not just towards his bhaiya and bhabhi. After all he is now married to Paridhi and she has to be his priority. He's just like the captain of a sinking ship trying to help other people's sinking ship. We can't help other people unless we are able to help ourselves first and this is what Prateek needs to be doing.
He interferes so much in his Yash Bhaiya and Aarti Bhabhi's life and focuses his time and energy only in that. As a result his relationship with Paridhi become restraint and they are constantly fighting with one another. He should give himself and his marriage more focus and more energy before interfering with other couples. He needs to see it for himself that his marriage is also in the middle of problems as love is not the only important thing in a marriage. There are so many people who enter into marriage or relationships because they love one another. If love is the ultimate and only important thing in a marriage then it will be enough to save those fail marriages and relationships and greatly reduce the amount unquestionably high rate of divorces.
The second thing is nobody wants to be constantly compared with someone else. And this is what Prateek is doing to Paridhi. He puts Paridhi in a pedestal hoping that she will be the ideal wife and bahu just because of their love and entering that relationship as a love marriage. He constantly want Paridhi to change from what she is now to be the same with Aarti who is loving, caring and understanding and be her shadow. Anybody in Paridhi situation will be irritated, angry and hurt at constantly being compared with anybody else and especially from those that we love.
And last but not least Prateek really needs to grow up. He is married now and he really needs to take responsibility of things stuffs anything. He also needs to have the guts to do something or take some decisions, not always listening or waiting for the verdict of the elders. Every decision he took it was always from the elders. I know that we need to respect the elders especially those of our own house and community, but those elders are not going to be with us all the time. Eventually elders and their children by circumstances whether it is by decisions or time will be separated from each other. By this the young needs to be the new elders and need to guide the next generations. If all his decisions were taken by the elders then how does he prepare himself for the future.