Is obedience to grandparents to be given precedence over obedience to parents when commands conflict, especially since obedience to grandparents may be considered part of obedience to parents?

First, it is preferable to combine showing dutifulness to both parents and grandparents. However, parents are given precedence when there is a conflict, because they are the direct cause of a person's existence. Their right comes immediately after the right of Allah Almighty. Allah Almighty says: "And your Lord has decreed that you not worship except Him, and to parents, good treatment." The mother is given precedence over the father, then the closer, and then the next closer among grandparents. The term "parents" includes grandfathers and grandmothers. It is recommended to give precedence in dutifulness to the mother, then the father, then the children, then the grandparents, then the brothers and sisters, then all other unmarriageable kin (mahrams).