A:
Visiting the graves for sending peace, supplicating to Allah to have mercy on the deceased and taking warning from their condition is Mashru` (Islamically prescribed), as the Prophet (peace be upon him) did so and said:
Visit the graves for they remind of the Hereafter.
Accordingly, there is nothing wrong if you visit the grave of your father and supplicate to Allah for him, facing the Qiblah and having his grave in front of you. All praise is due to Allah.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.