What is the ruling of Islamic law on opening graves to bury a deceased person with those previously buried, and is it permissible not to carry out a mother's will to be buried with her parents who died 40 years ago in a distant place, especially given that her husband and son are buried in other locations?

It is permissible to transport the deceased from their place of death to another location for a legitimate, recognized Sharia purpose, provided it is done respectfully and without harming the remains.

However, opening a grave to bury another deceased person on top of a previous one, or alongside them, is not permissible due to the violation of the sanctity of the dead. It is permissible to bury the deceased mother in a separate grave next to her father's grave, but it is not permissible to bury her with him in the same grave.

If transporting the deceased would result in harm or hardship, the mother should be buried in the nearest Muslim cemetery.