The answer to this question is yes; for as we can rightly conclude from the authentic sources of Islam, your father can know when you visit him; he will also be able to hear and return your greeting, besides benefiting from your du’as and good deeds on his behalf.
To further clarify the issue: This question belongs to an area or realm which is beyond the confines of logic, reason or experimentation: It belongs exclusively to the area of revelation.
As far as we can know from the revelation, it is clear that those who are buried in the grave not only know their visitors, if they had known them prior to their death, but also return their greetings.
The Prophet, peace be upon him, has left us clear instructions to visit the graves of our relatives and friends, to greet them and to offer prayers for them. This is lest we forget them after their death; through frequent visits to their graves we renew our relationship with them, invoke Allah’s mercy upon them, besides reminding ourselves of our final destination in the next world.
Such instructions, it is clear upon pondering, have meaning only if they are able to know their visitors and are able to return their greetings.
Imam Ibn Abd al-Barr, in his famous work kitab al-Tamhid, has cited the following report on the authority of Ibn Abbas: The Prophet, peace be upon him, said, “If a Muslim were to pass by the grave of his believing brother whom he used to know in this world and greet him, the latter would recognize him and would return the same.”
The Prophet, peace be upon him, further taught us to visit the graves of our relatives and friends and offer salutations/greetings thus:
Assalaamu alaikum diyaara qawmin mu’mineen wa inna inshaa Allaah bikum lahikun yaghfiru Allah lanaa wa lakum wa li saa’iri al-mulsimeen
(Greetings of peace to You O believers, dwelling in these residences; with Allah’s leave we will also be joining you in the near future; may Allah forgive us and you and all the Muslims).
Furthermore, referring to the disbelievers who were slain in the battle of Badr, the Prophet, peace be upon him, said, “Surely you are not better able to hear me than them; but the only difference is that they cannot respond to me!”
To conclude: You should continue to visit the grave of your father and greet him and offer prayers and supplications on his behalf; insha Allah, he will be able to know you when you visit him. May Allah grant us sound understanding of our religion and sincerity in practicing it-aameen.