What is the ruling on lying to one's family to complete a marriage, and is it obligatory to inform the family of the truth despite the wedding date being close?

There is no harm in lying to reconcile family members if this outcome cannot be achieved except through lying. This is one of the situations in which lying is permissible, based on the Prophet's (peace be upon him) saying: "He is not a liar who reconciles between people, narrating good or saying good," and his saying: "I have not heard of anything in which people are permitted to lie except in three: war, reconciling between people, and a man's conversation with his wife." However, what you promised your wife must be fulfilled.