Can a man marry his ex-wife, with whom he has three children, without the consent of her father, who opposes their reunion?

If a man divorces his wife with a revocable divorce (first or second), he is permitted to take her back during her waiting period (iddah), even if she dislikes it. However, if a minor separation (baynunah sughra) occurs (such as a divorce for compensation, or the expiration of the iddah without reconciliation), she is not permissible for him unless through a new contract that fulfills the conditions, including the presence of a guardian (wali). This is based on the Prophet's (peace be upon him) saying: "There is no marriage except with a guardian," and "Any woman who marries without the permission of her guardian, her marriage is invalid." However, if the husband is compatible (kufu') and the guardian refuses to marry her off without a valid reason, he is considered an adil (one who unjustly prevents marriage), and the guardianship transfers to the next in line. If they all refuse, the judge marries her off, based on Allah's saying: "So do not prevent them from marrying their [former] husbands if they agree among themselves on reasonable terms." (an tatadhulūhunna an yankihna azwājahunna idhā tarāḍaw baynahum bil-marūf) And adl is preventing a woman from marrying a compatible man if she desires him. The considered compatibility is compatibility in religion.