Is it permissible to visit graves, despite what was said that the Messenger did not visit his children and wives there, and does the recitation of the Qur'an reach the deceased, or only supplication, and should a Muslim only approach the entrance of the graveyard and not enter a specific grave to pray for mercy upon his relatives?

"It is incorrect to assert definitively that the Prophet, peace and blessings be upon him, did not visit the graves of his wives and children. Many of them were buried in Al-Baqi', and the Prophet, peace and blessings be upon him, used to visit the people of Al-Baqi' and pray for their forgiveness. As for those who died in Mecca, such as Khadijah and his son Al-Qasim, it cannot be definitively asserted that he did not visit their graves, for not knowing something does not mean it did not happen. It is authentically reported that he visited his mother's grave and wept, even though she died not upon Islam. Visiting a specific grave to pray for mercy upon the deceased is permissible, and the Prophet, peace and blessings be upon him, placed a stone on the grave of Uthman ibn Madh'un, may Allah be pleased with him."