First of all if it was an ancestral property, the grandfather will not have full rights over the property, he cannot partition the property as per his will to anyone with shares of any amount at his discretion. However, since he has given away a share to his wife by way of partition, we can presume that it was his share of property out of the ancestral property and he had transferred it to his wife.Thereby his wife becomes the absolute owner of the property by which, she has full rights to dispose the same in any manner as per her desire, hence her action of transferring her share of property to any one cannot be questioned by others,she is at liberty to do so and need take consent from anyone for this.