1) If the sale agreement is signed and its registered one needs to check all clauses in it.
2) whether the payment amount is mentioned in the agreement or part payment done at the time of agreement or with the full wish of all uncle's and anuty's the land has been transfer of ownership on that purchaser uncle or sold to third party for a reasonable cost.
3) All the facts needs to be checked at the agreement took place and in whose possession the land is as of now.
4) whether it was parents inherited property or ancestral property? All the facts and issues should be checked from each view of the corner.
5) for every transaction there is time limit to sue in the court as per limitations act.