What should a Muslim son do for his kaafir father when he dies?

Praise be to
Allaah.

It was narrated in a saheeh hadeeth that Naajiyah ibn
Ka’b narrated that ‘Ali ibn Abi Taalib (may Allaah be pleased with him)
said: “I said to the Prophet

(peace and blessings of Allaah be upon him), ‘Your old, misguided uncle
has died (he was referring to his father Abu Taalib). Who will bury
him?’ He said, ‘Go and bury your father.’ [I] said, ‘I will not bury
him, for he died as a mushrik.’ He said, ‘Go and bury him, then do not
do anything until you come to me.’ So I went and buried him, then I
came to him with traces of dust and earth on me. He told me to wash
myself, then he made du’aa’ for me in words that were more precious
to me than everything on earth.” 

(al-Silsilah al-Saheehah, by al-Albaani,
no. 161) 

The Shaykh said, commenting on this hadeeth: 

1 – It is allowed for the Muslim to take
care of the burial of his mushrik relatives. That does not cancel out
his hatred of their shirk. Do you not see that ‘Ali (may Allaah be pleased
with him) initially refused to bury his father for that very reason,
as he said, “he died as a mushrik.” He thought that if he buried him
when this was the case, that this was included in the forbidden kind
of friendship as referred to in the aayah (interpretation of the meaning): 

“O you who believe! Take not as friends
the people who incurred the Wrath of Allaah”

[al-Mumtahinah 60:13] 

When the Prophet

(peace and blessings of Allaah be upon him) repeated the command to
bury his father, he hastened to obey him and he gave up the notion that
had initially occurred to him. This is what obedience means: that a
person gives up his opinion in response to the command of his Prophet

(peace and blessings of Allaah be upon him). It seems to me that a son’s
burying his mushrik father or mother is the last act of good companionship
that the son can do for his mushrik parent in this world. But after
the burial, he cannot make du’aa’ for him or pray for forgiveness for
him, because of the unambiguous words of Allaah (interpretation of the
meaning): 

“It is not (proper) for the Prophet and
those who believe to ask Allaah’s forgiveness for the Mushrikoon, even
though they be of kin”

[al-Tawbah 9:113] 

If this is the case, then how can people pray for mercy
and forgiveness in the pages of newspapers and magazines for some of
the kuffaar, in death announcements for money! Let the one who has any
concern for his hereafter fear Allaah. 

2 – It is not prescribed for him to wash
or shroud a kaafir, or to offer the funeral prayer over him, even if
he was a relative, because the Prophet

(peace and blessings of Allaah be upon him) did not tell ‘Ali to do
that. If that were permissible, he

(peace and blessings of Allaah be upon him) would have said so, because
it is well known that it is not permitted for the Prophet

(peace and blessings of Allaah be upon him) to delay explaining something
at the time when that information is needed. This is the view of the
Hanbalis and others. 

3 – It is not prescribed for the relatives
of a mushrik to follow his funeral, because the Prophet

(peace and blessings of Allaah be upon him) did not do that in the case
of his uncle, although he was the one who was the most kind and compassionate
towards him, and he even prayed to Allaah to make his punishment the
lightest punishment in Hell. 

In all of that there is a lesson for those who are deceived
by pride in their lineage and who do not strive for their Hereafter
with their Lord. Allaah indeed spoke the truth when He said (interpretation
of the meaning): 

“there will be no kinship among them
that Day, nor will they ask of one another”

[al-Mu’minoon 23:101] 

al-Silsilah al-Saheehah
by al-Albaani, p. 94