Is it permissible to move the deceased mother's body based on her initial will and her brother's will, taking into account the nature of mixed cemeteries and the periodic payment system for grave maintenance, or should she be left in her current grave, and is it possible to move her grave closer to her husband's grave within the same cemetery?

It is forbidden to exhume a deceased person and remove them from their grave, except for a legitimate Shar'i reason, such as moving them from usurped land, or if they were buried facing a direction other than the Qibla (definition), or if there is a need to improve their shroud, or to bury them in a better plot of land, or next to a righteous person, or if they were buried due to an excuse without ghusl (definition) (ritual washing) or hanut (perfuming), or to separate them in a grave from someone buried with them. It is not permissible to exhume a grave for the purpose of moving the deceased to another location without necessity; rather, moving the deceased is disliked. As for placing the deceased in a coffin, it is disliked unless there is a need, such as if the ground is damp. If you are forced to do so, there is no sin upon you.