What is the ruling on attending the wedding of the husband's brother who lives in a Western country, does not pray, commits unlawful acts, and has civilly married a non-scriptural woman? Is it permissible to accept the invitation to this grand wedding?

This man is in great danger for abandoning prayer, which is a grave offense. Marriage to a non-Kitābīyah (woman of the People of the Book) is not permissible and is invalid. Cohabiting with her is considered adultery and illicit intercourse, due to Allah’s saying: ﴿And do not marry polytheistic women until they believe.﴾ It is not permissible to attend this wedding. It is obligatory to advise this man and instill in him fear of Allah the Almighty. If the woman embraces Islam, then marriage to her becomes permissible at that time. If the woman desires to learn about Islam, a way should be sought to communicate with her and guide her to the entities and institutions from which she can benefit.