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.
We have already highlighted the ruling and conditions of family meetings in some fatwas; please refer to fatwa 10463 in this regard.
There is no doubt that among these conditions is that women should adhere to the hijaab.
If some customs that prevail in the Muslim community involve some Islamic prohibitions, then they are bad customs and one should warn people against them and advise those who practice such habits as they are a source of temptation and a door for the devil to incite evil.
Tameem Ad-Daari, may Allah be pleased with him, narrated that the Prophet said, "Religion is advice." [Muslim]
If people do not stop, then one must leave that gathering, as it is not permissible for a Muslim to stay in a place where evil is taking place without having a sound reason for staying.
Allah says (what means): {And when you see those who engage in [offensive] discourse concerning Our verses, then turn away from them until they enter into another conversation. And if satan should cause you to forget, then do not remain after the reminder with the wrongdoing people.} [Quran 6:68]
Jaabir, may Allah be pleased with him, narrated that the Prophet said, "Whoever believes in Allah and the Last Day should not sit at a table where alcohol is served." [At-Tirmithi]
Indeed, you did well by leaving such gathering for fear of being sinful; so may Allah reward you and protect you from every evil.
Allah knows best.