The Ruling on Praying for the Forgiven for One Who Commits Major Sins

Question:
A man died while addicted to intoxicants, committing unlawful sexual intercourse, and killing the soul that Allah has forbidden. Does he deserve to be prayed for after death?

Answer:
If he was a known Muslim, known to be one who affirms the oneness of Allah, a Muslim who believes in Allah and the Last Day, but was afflicted with these sins, then there is no harm in making du'a' for him. May Allah forgive us, him, and the Muslims. One should pray for his forgiveness and mercy, because sins do not take one out of Islam. Intoxicants, unlawful sexual intercourse, and the like do not take one out of Islam according to the people of the Sunnah and the community, but his faith would be weak.
However, if he was known for something else that indicates his disbelief, such as insulting the religion, denying the obligation of prayer, denying the obligation of zakah, or mocking the religion, then he is a disbeliever. One does not make du'a' for him, nor does one pray for his forgiveness. But if he was known for loving Islam, and being a Muslim who prays and affirms the oneness of Allah, not associating anything with Allah, but was afflicted with these filth, these sins, then one makes du'a' for him, and his affair is left to Allah.