Drinking alcohol is a major sin because of the hadd punishment that is prescribed for it in this world, and the stern warnings of punishment for it in the Hereafter. Allaah says (interpretation of the meaning):
“O you who believe! Intoxicants (all kinds of alcoholic drinks), and gambling, and Al‑Ansaab (stone altars for sacrifices to idols etc), and Al‑Azlaam (arrows for seeking luck or decision) are an abomination of Shaytaan’s (Satan’s) handiwork. So avoid (strictly all) that (abomination) in order that you may be successful”
In Saheeh al-Bukhaari (2295) and Muslim (86) it is narrated that Abu Hurayrah (may Allaah be pleased with him) said: The Prophet (peace and blessings of Allaah be upon him) said: “No adulterer is a believer at the time when he is committing adultery; no thief is a believer at the time when he is stealing; no drinker of wine is a believer at the time when he is drinking it.”
i.e., he cannot be a believer at the time when he is drinking it, and his faith is greatly diminished by this abhorrent action.
In Sunan Abi Dawood (3189) it is narrated that Ibn ‘Umar (may Allaah be pleased with them) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Allaah has cursed alcohol, the one who drinks it, the one who pours it, the one who sells it, the one who buys it, the one who squeezes it (squeezes the grapes, etc), the one for whom it is squeezed, the one who carries it and the one to whom it is carried.” (Classed as saheeh by al-Albaani in Saheeh Abi Dawood, 2/700)
What the one who has drunk it must do is hasten to repent sincerely, give it up completely, resolve never to go back to it, and regret what he has done.
As alcohol is completely forbidden, as we have explained, then selling it is also haraam. The Prophet (peace and blessings of Allaah be upon him) cursed the one who sells it and the one who buys it.
As for the wealth that comes from dealing in alcohol, that is subject to further discussion:
1 – If it is still there it must be got rid of, by giving it to the poor and needy, and donating it to charitable causes, because it is impure wealth that is not permissible for the one who acquired it.
It says in Fataawa al-Lajnah al-Daa’imah (14/61) concerning one who acquired wealth by selling haraam things such as alcohol:
The Prophet (peace and blessings of Allaah be upon him) said: “O people, Allaah is Good and only accepts that which is good. Allaah commanded the pious to follow the same commandments as He gave to the Messengers. He says (interpretation of the meaning):
‘O (you) Messengers! Eat of the Tayyibaat [all kinds of Halaal (lawful) foods which Allaah has made lawful (meat of slaughtered eatable animals, milk products, fats, vegetables, fruits)] and do righteous deeds. Verily, I am Well-Acquainted with what you do’ [al-Mu’minoon 23:51]
‘O you who believe (in the Oneness of Allaah — Islamic Monotheism)! Eat of the lawful things that We have provided you with’ [al-Baqarah 2:172]
Then he mentioned a man who has travelled on a long journey and is dishevelled and covered with dust; he stretches forth his hands to the heaven, (saying) “O Lord, O Lord”, but his food is haraam, his drink is haraam, all his nourishment is haraam, so how can he du’aa’ be accepted?” Narrated by Muslim in his Saheeh.
Hence it haraam for the Muslim to deal in haraam things. The one who does any such thing must repent and give up the haraam earnings. There are many permissible ways of earning a living – praise be to Allaah. Allaah says (interpretation of the meaning):
“And whosoever fears Allaah and keeps his duty to Him, He will make a way for him to get out (from every difficulty).
3. And He will provide him from (sources) he never could imagine”
If a person repents and has wealth that he acquired by haraam means, such as riba and gambling, or selling haraam goods such as alcohol and pork, he must get rid of that wealth by donating it to public projects, such as repairing roads and public washrooms, or he may distribute it to the needy. He should not keep any of it or benefit from any of it because it is haraam wealth in which there is no goodness. Repenting from that means that he must get rid of it and keep away from it, and find another way of earning a living. End quote.
But if he was a kaafir at the time he sold the alcohol, then he became Muslim, then he does not have to get rid of this wealth, because the Messenger of Allaah (peace and blessings of Allaah be upon him) did not oblige the Sahaabah to get rid of the haraam earnings that they had when they became Muslim.
2 – If he has spent the money and used it to build a house or buy a car, then he does not have to do anything except repent. So he should repent to Allaah and make use of the house or car, but he should give a lot of charity and do a lot of righteous deeds. See also the answer to question no. 78289.
And Allaah knows best.