I am 20 years old; all my friends are Western. Is it lawful to go out with them while they are drinking alcohol?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

A Muslim should not take non-Muslims as friends, since such company leads to serious dangers and big distress.

The Prophet said: “Do not accompany but a believer, and only a pious one should be allowed to eat your food.” [Ahmad, Abu Daawood and At-Tirmithi]

In addition, taking bad friends results in several kinds of evil, among which are the following:

1) It is part of human being's nature to be influenced by his friends; i.e., positively or negatively. The first quality (positively) is good but here we mean the second (negative influence). Thus, the Prophet said: “A man is upon the religion of his friend, so let one of you choose whom he befriends.” [Ahmad, Abu Daawood and At-Tirmithi]

2) Great loss in the Hereafter when one's bad friends will abandon him. Allah Says (what means): {Close friends, that Day, will be enemies to each other, except for the righteous.} [Quran 43: 67]

3) One will be resurrected with whom he loves. The Prophet said: “A person will be (in the Hereafter) with whom he loves.” [Al-Bukhari and Muslim]

As for going out with those people while they are drinking wine, then it is definitely forbidden since it will result in disobedience to Allah, such as being silent concerning what is forbidden being done.

In this vein, the Prophet said: “Whoever believes in Allah and the Last Day should not sit at a table where intoxicants are served.” [At-Tirmithi and Ahmad]

Abu Daawood's narration includes the following addition: "Where wine is drunk."

‘Umar Ibn 'Abdul 'Azeez beat a group of people who were drinking wine, and when someone told him that there was a fasting person among them, he said: “Beat him first”, and he recited the verse in which Allah Says (what means): {And it has already come down to you in the Book that when you hear the verses of Allah [recited], they are denied [by them] and ridiculed; so do not sit with them until they enter into another conversation. Indeed, you would then be like them. Indeed Allah will gather the hypocrites and disbelievers in Hell all together.} [Quran 4: 140]

For more benefit on being present at a place where alcohol is served or drunk, please refer to Fataawa 351544, 90464, 86497, 85631, and 82521.

For more benefit on the prohibition of alcohol in Islam, please refer to Fataawa 81900, 81389, and 81461.

Allah knows best.