I have been thinking of teh same thing since Yash came to know about Akash being the son of Gayathri. It intensified after Gayathri's behaviour and if they really show that she bad mouths Radha saying " to give your illegitimate son the rights in SM, you stole and deprived my son's rights". The moment Yash hears this, he will transfer all the property in his name (from Sindhia household) and leave the place with his wife and kids saying he is indebted for the education and experience they gave to him and with that he will live his life else where with his family away.
May be he will convince Sp on this even before some one (either Gayathri or Ishitha) pin points him or Aaarti on the same. I have strong feeling that Gayathri will bad mouth aarti by calling her scheaming (for all her efforts to bring in Akash) as to restore their (arya) place in the family.
Jaya