The self acquired property of the deceased person devolves upon his legal heir if the deceased dies intestate (without making a will). So far as ancestral property is concerned the coparceners of Hindu undivided family get share in the ancestral property by birth. Therefore, a Hindu cannot alienate ancestral property by making a testamentary will. The legal heirs can divide the self acquired and ancestral property either by filing a partition suit or through a family settlement deed.
The “Karta” or manager of the joint Hindu family can sell the ancestral land. His power to alienate the ancestral property has some restrictions. He can sell the land for the legal necessity and for the benefit of the family. Only male coparcener can discharge the duty of “Karta”. Your grandmother could not perform the duty of “Karta” because she is not a coparcener.