 our prophet muhammad may god bless him and grant him peace asked permission to visit his mothers grave and to seek forgiveness. he was given permission to visit but not to seek forgiveness for her.
وإن نبينا محمد صلى الله عليه وسلم استأذن فى زيارة قبر أمه.. وفى الاستغفار فأذن له فى الزيارة ولم يؤذن فى الاستغفار لها..