Sheikh Salman al-Oadah
Regarding our Prophet’s (peace be upon him) mother, it has been mentioned in authentic hadîth that the Prophet (peace be upon him) said: “I had requested from Allah to let me ask Him to forgive my mother, but He did not allow me to do so. Then I requested Him to allow me to visit her grave and He allowed me. Visit the graves, since they remind us of the Hereafter.”
Allah did not allow him to ask forgiveness for his mother; therefore, we can only say that her fate is up to Allah.
Regarding the father of our Prophet (peace be upon him), it is mentioned in Sahîh Muslim that a man asked the Prophet (peace be upon him): “Where is my father?” The Prophet (peace be upon him) replied: “In Hell.” When the man turned to leave, the Prophet (peace be upon him) called him and said: “My father and your father are in Hell.”
However, this should not be mentioned all the time, unless there is a need to mention it, particularly since it may bring unnecessary sadness to some Muslims. The Prophet (peace be upon him) said: “Do not revile the dead so you hurt the living.”
Source: Islam Today