What are the restrictions that I have to keep between me and my friend who drinks wine?

Answer

Praise Be to Allah and Peace Be Upon His Messenger.

Drinking wine is haram (unlawful), and this is stated in the Holy Qur’an and Sunnah. All scholars have also agreed that drinking wine is haram. It is considered one of the heinous sins. Allah says: “O you who believe! Intoxicants (all kinds of alcoholic drinks), and gambling, and Al-Ansab (idols), and Al-Azlam (arrows for seeking luck or decision) are an abomination of Shaitan’s (Satan) handiwork. So, avoid (strictly all) that (abomination) in order that you may be successful. Shaitan wants only to excite enmity and hatred between you with intoxicants (alcoholic drinks) and gambling, and hinder you from the remembrance of Allah and from As-Salat (the prayer). So, will you not then abstain.” Al-Ma’idah: 90-91

The Islamic Shari’a urges Muslims to advise each other by enjoining good and forbidding evil to ensure that they get what is good in this life and in the Afterlife. The messenger of Allah says: Religion is sincere advice; we said: “To whom should it be directed O messenger of Allah?” He said: “To Allah, To His book, to His messenger, to the Imam of Muslims, and to Muslims in general.”

Thus, it is a duty to advise your friend and tell him the ruling on consuming wine, and how serious this sin is. You should persist on advising him but kindly. It is fine if you also pray to Allah to help him quit drinking, but you should be cautious that the relationship between you and him should not have any bad effects on you.