Is the marriage contract considered null and void if the wife's representative was her younger brother in the presence of her father and older brother due to an old dispute?

The woman's father is the one who has the most right to marry her off, and her brother has no guardianship if the father is present. If the father is present and can be communicated with, and he does not refuse to marry his daughter to a suitable man, then the marriage is invalid according to the majority of scholars and must be annulled immediately. To renew the contract, it must be in the presence of her guardian who has the most right to marry her off. This marriage becomes valid and proceeds if a Sharia judge rules it to be sound. As for the children, they are attributed to you in all cases.