Please enlighten on the point that can both the floors would devolve on the brothers wife automatically?
Since it is intestate property, the legal heirs of your brother shall be entitled to the entire property that is remaining on his name.
However instead of going round about way, you can discuss with your sister in law and getting some elders of the family involved in this meeting you may arrange for a family settlement and accordingly draw a deed apportioning your share in the property, get the deed registered, take possession of the property, transfer all records of the property allotted to you to your name.
Could you please suggest me other possible ways considering the below points
1) If I am able to arrange the original will
2) If I am not able to arrange the original will
If the will is not signed by a witness, then getting a original will is also of no use.
To enforce the will it has to be probated since the other heirs would not be willing to give NOC.
In my opinion, if nothing works out, you may file a partition suit on the basis of the original status of the property and seek your share in it, let them defend themselves with whatever they would try to defend.