Thank you for your advice in my case.I do have a few more clarifications.
I understand that the relinquishment deed is registered, but the value of the  residential property stated in the family settlement was like one fifith of its true value at that time.Its not about stamp duty, its about the amount that was paid to me was less than the true value of the property.Is there any way I can challenge the family settlement and the relinquishment deed like saying that I did it earlier out of trust and regard for my sister but she cheated me out of my true share?
Regarding my brother's property- the commercial one-- is there any way I can represent my brother and challenge the trust deed,though the property never belonged to me, but my brother is a weak character who again signed the trust deed because he was manipulated by my sister.I have a signed affadavit by him that says that he has no recollection of signing these documents,and also a will that says that he wants the property to be shared equally by his two sisters after him.( the affadavit is registered but the will is not)According to the trust deed however, the property with all its income will be transferred to the name of the beneficiary which is my sister's son after 17 years, when he is 21 years old.( regardless of whether my brother is alive or dead-- currently he is unmarried and has no issues)
the trust deed is registered---is it true that I or anyone  cannot challenge this trust after 3 years of its making??
Does my brother's  will have no value if he has transferred this property in the name of the trust during his lifetime?
My sister and brother in law have no guilt or shame for what they have done and feel they have full right on the property and my brother's share because he lives with them.Becuase he lives with them he also finds it difficult to challenge the trust deed because now that he has no rental income, he feels dependant on them.
I appreciate your advice and would be willing to answer any other questions you might have.
 
Thanks
 
Dr Batra