Twins confusion

Alright so this is what i've gathered so far. Mostly everyone thinks that the other twin doesn't exist. How is that possible? And suhani gave birth to them she should know that the other twin was alive because the doctor would of told her... any theory?

Honestly I dnt knw hw they can pass of the twins as twins. Yuvani she looks really big she looks atleast 4/5 years older then Yug. Yug is so sweet bt he cnt even speak properly some times. U can see the kid is a baby. If they really thought that the kid playing Yuvani was perfect for the role they should have adjusted the storyline. Killed of 1 twin, show another reason for yuvani breaking up and afterwards suhani being pregnant again. And these not so twin looking kids would make perfect sense. I am also wondering hw did both of them get the kids. I wonder if dadi stole yuvani away from suhani. And even if she did steal it away how did Yuvraj get the baby, does he think that suhani gave him the baby or did he take the baby away from suhani without her knowledge.