Sa'id bin al-Musayyib narrated that the mother of Sayyiduna Sa'd bin Ubadah (may Allah be pleased with him) died while he was away. When he returned, he said: "O Messenger of Allah, I would like you to offer the funeral prayer for my mother." So the Prophet (peace and blessings be upon him) went to her grave and offered the funeral prayer for her, even though a month had passed since her death.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5359