I fink that soham an kavya were twins guys. I konw this sounds really dumb, but this is my theory.
When kavya was about 2 be born nitya was obviously evil, as we all know. Now im guessing that if she was willing 2 kill ved when he was jus a defenseless newborn then why would'nt she kill kavya when he was born? I mean she didn't know about mayank's will stateing that kavya had 2 be pagal 4 her 2 inherit his wealth then did she? I fink she probably did make a plan 2 kill kavya.
But there was one small problem. Kavya's mom gave birth 2 twins. U see thsi threw Nitya of course then. Now instead of kidnapping an killing one baby she had 2 kidnap an kill 2. But she only managed 2 kidnap one of them. An that was little baby soham. But even then sumhow baby soham survived, an was brought up far away from kavya an the nanda's.
Anywayz nitya probably always thought that soham was killed at birth until she saw him one day. Then she paniked but decided that as soham didn't know anyfink about being connected 2 the nanda's that she was safe. So soham was allowed 2 live.
But when nitya started 2 care about kavya an finally turned gud, she decided 2 tell kavya all about soham. An when kavya found out the truth he became determined 2 find his brother an reunite wit the nanda's. But unfortunetly 4 kavya when he finally found soham, he was either dead or dying. This wud probely be happening around the same time that this wholw nimila/property business was going on. Infact he probably knew that sumone wnted 2 kill him. He must hve suspected nimila an sons but didn't hve any proof 2 prove that it was them. So clever kavya decided 2 fake his death, by passing off soham's dead body as his own. As we all know that plan went off witout a hitch. It really was kavya who risked his life 2 save ved in the fire, but although he almost died, he pulled through. But still this was 2 gud an opportunity 2 miss, so that's when the plan 2 fake his death came 2 his mind.
Alas soham was only reunited wit the nanda's at his own funeral. Anywayz now kavya is pretending 2 be soham 2 the whole world in an attempt 2 find proof against nimila an her family. He even made angali hate him so that she does'nt ever suspect him of really being kavya. Afterall kavya wud ever act like he was willing 2 force himself on angali, so therefore she wud never ever guess that was indeed kavya. Also he probably did suspect shauraya of foul play, but now he knows the truth. That it was yug.
Well that's my theory guys. Its probably really far-fetched but its the only way that i can imagine soham turning in2 kavya later on in the show.