Sir if brother has no child and already separated from wife with a decree of the court. then you and mother are joint owners of the property and the mother can make a gift deed to you or your daughter or whom so ever she want for her 50 percent share further she can also make a relinquish deed in your favour as you are co-owners.
for rest 50 percent you are owner.
Further file an application before municipal department with the copy of Death certificate of father brother and divorce decree to mutate the land in name of you and your mother. Then the above mentioned deed can be made.