Veelunama(will)

Please check in whose name the land is? Please check all the revenue records like Adangal Pahanis, Pattadar Passbooks, Title Deeds and Source of Title...Then you can come to clear idea, who is the real owner...If your Grandfather is the real owner, then your Grandmother has no right to execute such will, but she will be eligible for her share along with other family members....If the land is in the name of your grandmother, then she has every right to execute the will....

If the property is still on your grandfather's name, in the capacity of his  legal heir and as a share holder, your grandmother can execute a Will bequeathing her share of the property out of the undivided intestate property in favor of anyone she may desire to, thus she can execute a Will duly attested by two witnesses in respect of the property to which she has a perfect title.