According to a Hadith in Al-Tirmidhi, it was narrated by Hadhrat Abu Darda (Radi Allah Anho) that alcohol is the key to all evil; this is consuming it or selling it. It is totally Haraam to sell alcohol and the income earned is also Haraam.
It is Haraam for a Muslim to sell something that is Haraam for him to eat or use. The Holy Prophet, Hadhrat Muhammad-ur Rasullullaah (Sallallaahu Alayhi Wasallam) said, “If Allah Taa’la makes Haraam the consumption of something; He also makes Haraam its transaction.” (Musnad Ahmad, Hadith no. 2546)
Islam is a consistent religion. When it says that something is bad and forbidden, then it wants Muslims to avoid it for themselves and for others. If a Muslim sells Haraam things, he is not only inconsistent in his behaviour; he is also ridiculing the law of Allah Taa’la. He does not care what is right and what is wrong. It is right if other Muslims avoid business with this person. This will be a good reminder for this person to come back to the rules of Allah Taa’la.
Hadhrat Anas (Radi Allah Anho) says that the Holy prophet, Hadhrat Muhammad-ur Rasullullaah (Sallallaahu Alayhi Wasallam) cursed ten people in connection with wine; the wine-presser, the one who has it pressed, the one who drinks it, the one who conveys it, the one to whom it is conveyed, the one who serves it, the one who sells it, the one who benefits from the price paid for it, the one who buys it and the one for whom it is bought. (Al-Tirmidhi) My advice to you is that within the boundaries of respect to your father, tell your dad that you cannot sell alcohol as it contradicts the teachings of Islam.
(VERILY, ALLAH TAA’LA IS ALL-KNOWING