Release deed after death

Y is not having valid title, then how can he can sell it to you,  Y cannot effect any transfer to you, even if other legal heirs effect release deed now. The only solution left is Y has to re convey the property back to X family and the whole family including all surviving  legal heirs should convey it to you, or they can issue release deed fvg one person of that family and the concerned person can do sale deed favg, you. after re conveyance  was done. It is cumbersome procedure, but u have no other alternative.

Thankyou Adv Raghavan.This is really helpful

There is no need to reconveyance.  The share to the extent of Y has already been transfered to you.  Now the rest of the family members share has to come to you.  As advised by Raghavan.  The share of rest of the family members i.e. 2 sons, 3 daughters, wife (widow) has to be released in favour of any one of the family and then it can be sold to you. Thus, there will be two sale deeds from the same family. 

I differ with the above contention to some extent, Y is not a family member, he is third person, and he holds a defective title, by a sale deed executed by mother and one son, ignoring all other legal heirs,and he does not have power to do sale deed, because his title is not clear and in valid, in this situation he cannot effect any transfer favg any other person The contention of his share being transferred does not hold any good here.

I agree with the opinion given by learned Advocate Mr. Raghavan on the subject.  The sale deed executed by the wife and one son of deceased X in favor of Y over the entire property is invalid and illegal.  It will not bind the other legal heirs of deceased X.  Now since the sale deed has already been registered  in favor of Y, release deed by other legal heirs in favor of any one of the legal heir of the family will be considered as invalid because the same has to find a place in the recital of the original sale deed executed and registered in favor of Y in the year 1996.   Therefore the only remedy is that Y has to re-conveyance the property to the previous vendors after which the sale deed can be affected in the way and manner as opined.