Fair?

Religion again guys!! Some food for thought:

"Mention in the scripture Abraham; he was a saint, a prophet.

He said to his father, "O my father, why do you worship what can neither hear, nor see, nor help you in any way?

"O my father, I have received certain knowledge that you did not receive. Follow me, and I will guide you in a straight path.

"O my father, do not worship the devil. The devil has rebelled against the Most Gracious.

"O my father, I fear lest you incur retribution from the Most Gracious, then become an ally of the devil."

He said, "Have you forsaken my gods, O Abraham? Unless you stop, I will stone you. Leave me alone."

He said, "Peace be upon you. I will implore my Lord to forgive you; He has been Most Kind to me.

"I will abandon you and the gods you worship beside GOD. I will worship only my Lord. By imploring my Lord alone, I cannot go wrong."

Qur'an 19:41-48

Abraham tells his father not to worship false gods and to worship his God, but Abraham's father is upset that his son denounces his gods. Abrahams says he will pray so that his God doesn't punish his father for not believing in him after Abraham has told him to.

Is it fair that Abraham's father would be punished for believing in different deities?

Fair:
1. The Qur'an assumes that Abraham's God is true
2. The Qur'an assumes that Abraham has a valid and believable argument for the existence of God
3. Therefore his father has just outright rejected God in the face of truth and reason

Unfair:
1. It seemed to me that Abraham didn't have a valid argument besides an oh hey you should believe me kind of thing
2. Abraham's father could be just as sure that his gods exist, and he wouldn't want to denounce them and risk their punishment
3. It seems unfair that God would give humans free will only to punish them for not choosing him, especially if he's omniscient and knew they would choose other deities if given the choice.

For the last two points especially, I'm inclined to think that it's incredibly unfair for Abraham's father to be punished, but I'd like to hear other thoughts on the topic.