It is guessed the Deceased mother (of Anita) and Anita are Hindu.
You have not posted how the proeprty was given by mother to Anita.
If a Hindu Female dies without disposing her property in her life time and without leaving a valid WILL then her property shall devolve equally upon husband, sons and daughters.
If mother was sole owner of the property and transferred the property by a valid deed to Anita then other siblings may not have a legal claim.
You may show all docs on record e.g. mutation record, link docs to a very able counsel specializing in family/property/revenue/civil matters..................for a considered opinion.