What should a girl do if the suitor's mother refuses her son's marriage to her, knowing that they are a very religious family?

A religious husband's desire for his wife's religiosity is a great blessing, but it must not be associated with forbidden relationships. The young man must persuade his mother with kindness and gentleness, and you must resort to Allah. It is not permissible to marry a specific woman if the parents refuse, for obedience to parents is obligatory, and what is obligatory takes precedence over what is not obligatory.