What is the religious ruling regarding the marriage of a divorced woman to a younger man, secretly contracted with one witness and without a mahr (dowry) or shabka (engagement gift), taking into account the wife's fear of her ex-husband concerning her children? And what is the way to rectify the situation if there is an error in it?

The majority of scholars hold that marriage is not valid without a guardian (wali), and a contract without a guardian is void. The ma'dhun (marriage officiant) who conducted the contract, his testimony is not accepted, due to the suspicion of his testifying on his own action. The mutual agreement of the parties not to take a 'shabka' (engagement gift) or a dowry does not invalidate the marriage. The woman and the young man committed a grave error by marrying without a guardian, and they must repent and desist. The children are attributed to the father based on the opinion of those who permit a woman to marry herself. If she wishes to marry him, she should refer the matter to her guardian. If the guardian refuses and the prospective husband is suitable, she should refer the matter to the judge to marry her. The mother has a greater right to the custody of the two children as long as she does not marry. If she marries, her custody rights fall, and custody transfers to the next most entitled person. The father has the right to claim custody of the children if he is just.