Challenging transfer deed

Dear Learned Friends, My father died (intestate) in 1978 leaving behind W, S1, S2, S3 & D1. Land falls in Lal Dora area (in Faridabad) meaning thereby no papers of any type are available wrt the same land. an oral partition took place between between all Sons and mother 20 years back. Wherein mother didn't take any share and hole property was divided equally among all sons. Now some time back, my mother (under impression as if she became owner property of the property after death of my father) made a Transfer deed wrt to the residential immovable property in favor of S2 & S3 giving them more share in the property. I wish to know whether :- 1. ) Whether rules of succession get affected in any way merely because of the fact that land falls in Lal Dora area. 2.) If I choose to challenge the said Transfer deed then it needs to be challenged during her lifetime or it can be challenged after her lifetime as well. What will be the consequences if same Transfer deed is challenged after her lifetime? 3.) Generally how long will it take to sort our if I approach court for making said Transfer deed null and void.