Inna Lillahi Wa Inna Ilayhi Rajiun, May Allah forgive his sins and grant him a place in Jannah .
Here are some authenic hadis which u can do as an ISALE-Sawab For your father
Among the deeds whose rewards we are allowed to give to the dead, or by means of which the dead can benefit from the actions of the living, are the following:
(i) Du’aa’
Allaah says (interpretation of the meaning):
“And those who came after them say: “Our Lord! Forgive us and our brethren who have preceded us in Faith…” [al-Hashr 59:10]
It was reported that Abu Hurayrah (may Allaah be pleased with him) said: “The Messenger of Allaah (peace and blessings of Allaah be upon him) told us of the death of the Negus, the king of Ethiopia, on the day that he died, and said, ‘Pray for forgiveness for your brother.’”
(Narrated by al-Bukhaari, 1236; Muslim, 951)
It was narrated that ‘Uthmaan ibn ‘Affaan said: “When the Prophet (peace and blessings of Allaah be upon him) finished burying someone who had died, he would stand over him and say, ‘Pray for forgiveness for your brother, and ask that he may be made steadfast, for even now he is being questioned.’”
(Narrated by Abu Dawood, 3221. An-Nawawi classed the isnaad of this hadeeth as jayyid in al-Majmoo’, 5/292).
Ibn al-Qayyim (may Allaah have mercy on him) said:
“The fact that the dead benefit from du’aa’s is indicated by the consensus of the ummah on offering du’aa’ for him during the janaazah (funeral) prayer, hence we know that du’aa’ benefits the deceased… This is supported by many ahaadeeth and is in fact is the whole point of praying for the deceased. The same applies to making du’aa’ for him after the burial, and making du’aa’ for them when visiting their graves.”
(al-Rooh, 118, 119)
(ii) Making up fasts that were obligatory upon the deceased because of vows, as expiation (kafaarah) and so on
It was reported from ‘Aa’ishah (may Allaah be pleased with her) that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Whoever dies and had any fasts outstanding, his heir should observe those fasts on his behalf.”
(Narrated by al-Bukhaari, 1851; Muslim, 1147)
It was reported from Ibn ‘Abbaas (may Allaah be pleased with them both) that a woman came to the Messenger of Allaah (peace and blessings of Allaah be upon him) and said, ‘My mother has died and she one month’s fasting outstanding.’ He said, ‘Do you not think that if she was in debt, you would pay it off for her?’ She said, ‘Yes.’ He said, ‘The debt owed to Allaah is more deserving of being paid off.’”
(iii) Paying off debts
It was reported that Salamah ibn al-Akwa’ (may Allaah be pleased with him) said:
“We were sitting with the Prophet (peace and blessings of Allaah be upon him) when a funeral bier was brought to him and they said, ‘Pray over him.’ He said, ‘Does he have any debts?’ They said, ‘No.’ He said, ‘Has he left anything behind?’ They said, ‘No.’ So he prayed over him. Then another funeral bier was brought to him, and they said, ‘O Messenger of Allaah, pray for him.’ He said, ‘Does he have any debts?’ They said, ‘Yes.’ He said, ‘Has he left anything behind?’ They said, ‘Three dinars.’ So he prayed over him. Then a third funeral bier was brought, and they said, ‘Pray for him.’ He said, ‘Has he left anything behind?’ They said, ‘No.’ He said, ‘Does he have any debts?’ They said, ‘Three dinars.’ He said, ‘Pray for your companion.’ Abu Qutaadah said, ‘Pray for him, O Messenger of Allaah, and I will take care of his debt.’ So he prayed over him.”
(Narrated by al-Bukhaari, 2169)
(iv) Fulfilling vows to do acts of worship
It was reported from Ibn ‘Abbaas (may Allaah be pleased with them both) that a woman from Juhaynah came to the Prophet (peace and blessings of Allaah be upon him) and said: “My mother vowed to go for Hajj, but she did not go for Hajj before she died. Should I do Hajj on her behalf?” He said, “Yes, do Hajj on her behalf. Do you not think that if your mother was in debt you would pay it off for her? Pay off the debt that is owed to Allaah, for Allaah is more deserving that what is owed to Him should be paid off.”
(Narrated by al-Bukhaari, 1754
(v) Performing Hajj on his behalf
It was narrated from Ibn ‘Abbaas that the Messenger of Allaah (peace and blessings of Allaah be upon him) heard a man saying “Labbayka ‘an Shubrumah (At your service, O Allaah, on behalf of Shubrumah).” The Messenger of Allaah (peace and blessings of Allaah be upon him) said, “Who is Shubrumah?” He said, “A relative of mine.” The Prophet (peace and blessings of Allaah be upon him) said, “Have you ever done Hajj before?” He said, “No.” he said, “Do this Hajj for yourself, then do Hajj on behalf of Shubrumah.”
(Narrated by Abu Dawood, 1811; Ibn Maajah, 2903 – this version was narrated by him. The hadeeth was classed as saheeh by Shaykh al-Albaani in Irwaa’ al-Ghaleel, 4/171).
(vi) Righteous deeds done by the children of the deceased
Shaykh al-Albaani (may Allaah have mercy on him) said:
“Whatever righteous deeds the righteous son does, his parents will have a reward like his, without it detracting from his reward in the slightest, because their child is part of their striving and earning. Allaah says (interpretation of the meaning): ‘And that man can have nothing but what he does (good or bad)’ [al-Najm 53:39]. The Messenger of Allaah (peace and blessings of Allaah be upon him) said: ‘The best that a man can benefit from is that which he earns, and his son is also part of his earnings.’ (Narrated by Abu Dawood, 2/108; al-Nasaa’i, 2/211. Narrated and classed as hasan by al-Tirmidhi, 2/287. There is a corroborating report in the hadeeth of ‘Abd-Allaah ibn ‘Amr, which was narrated by Abu Dawood, Ibn Maajah and Ahmad (2/179, 204, 214) with a hasan isnaad).”