Transfer of 100s of crs of private company shares on unprobated will

My grandmother is executor to my gramdfather's will. She did not show this will to other heirs and started to execute the will without their knowledge. She did not break any of the stipulations in the will. She simply transferred his private company shares to her name, which was permitted under his will. He had a large number of private companies, with land holdings worth 100s of crores. I have heard that in Delhi (which is where we live) no probate is required to execute a will. Was she permitted to transfer the private company shares using just the unprobated will?