Time Limit Of A Sale Agreeemnt

Subject B claims to have a sale deed of a property belonging to Subject N in the year 1991. Subject S is life long beneficiary of this property. Subject S passed away in 1998. Subject B produced the above-mentioned sale agreement in 2015 and filed a suit, which Subject N is not aware of executing any such agreement and informed the same to the court. Document verified and the signature of Subject N was claimed to be similar by expert opinion. Both the witnesses were also produced by Subject B and they claimed to be in his favor. Subject B also informed the court that, the subject repeatedly asked the subject N to execute a sale deed in his favor, but Subject N denied. other than the mentioned sale agreement, Subject B did not produce any evidence, like payment of money or any evidence of the purchase of stamp paper, etc. No specific timeframe for the execution of sale deed was mentioned in the sale agreement. Kindly advise. 1. What is the time limit of this sale agreement. 2. What is the validity of this sale agreement 3. Are there any points that can be raised in favor of Subject N and against Subject B. 4. Kindly cite some judgments and laws supporting Subject N and against subject B. Thank you.