Sa'id bin Jubayr (may Allah have mercy on him) said: A man came to Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) and said: My father has died as a Christian. He said: "Wash him, shroud him, apply perfume to him, then bury him." Then he recited this verse: "It is not fitting for the Prophet (peace and blessings be upon him) and those who believe to seek forgiveness for the polytheists, even if they are close relatives." [Surah al-Tawbah: 113]
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6667