Since it's obvious that Dadaji didn't bother about Ramesh the last 27 years, question is - why is he so determined to get Neeraj back? Initially, I thought that he had no male grandkids, but that's not the case, as he has Raj, Anmol & Jignesh's son & Nina's hubby.
Just as he's figured out that he needs Sandhya to get Neeraj to accept the family, I think he'll probably figure out that the best way to win Neeraj's confidence, trust & love permanently would be to get Sandhya to marry him. Therefore, I think it's not Neeraj, but Dadaji, who'll ask Sandhya to marry Neeraj. She won't be able to say no, and that'll be that.
As we saw today, Gayatri won't like that, and will probably try & blackmail Dadaji by threatening to reveal to Neeraj the fact that they didn't bother about his dad. Obviously, Dadaji won't want that, and will therefore be hostage to Gayatri's machinations.
So what's likely is that Neerdhya will marry, and find themselves in the midst of another series of games. I think that in the long run, they'll stay w/ the family, since everyone else in the family seems to genuinely love them. But how they handle Gayatri & Dadaji remains to be seen.