All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
There are some conditions for the validity of marriage without which the marriage is void, the most important of these conditions is the presence and consent of the guardian; for more benefit on these conditions, please refer to Fatwa 83629.
Therefore, if what you mentioned is correct that this marriage took place without the consent of the guardian, then it is an invalid marriage according to the view of the majority of the jurists . Hence, you should endeavor to convince this young man to divorce that girl even if it is in return for compensation; and this is what is called Khul’. For more benefit, please refer to Fatwa 89039.
In case this young man refuses to divorce or to grant Khul’, then the guardian of the girl should take the case to an Islamic judge if any, otherwise to any authority that is specialized in studying the personal matters of the Muslims.
However, this girl is not permitted to marry another man until her husband divorces her or that the judge invalidates their marriage as discussed in Fatwa 92478.
Finally, the following matters should be mentioned:
1- According to the most preponderant opinion of the scholars, what should be taken into account in marriage is the suitability in religion, and any other differences should not be taken into account.
2- The length of the period of this marriage and the lack of contact between that man and that girl, all this does not have any effect; rather, there must be a divorce or that the marriage is invalidated by the judge, so that divorce takes place.
3- The girl or her guardian should not hasten to accept a proposal for marriage before making sure about the religion and moral conduct of the person who proposes for marriage.
Allaah Knows best.