For good and valid reasons a bishop, through his chancery offices, can dispense from the required Catholic form of the marriage of a Catholic and Jew. In that case, the rabbi officiates at the ceremony and asks all the questions and receives the consent of both parties to the marriage. With a dispensation from the form, such a marriage is valid and is recognized by the Church as a true marriage.
If your prospective in-law finds a rabbi who will officiate at the marriage, that rabbi might not agree to having a priest share in the service.
If that is the case, encourage your child to obtain the necessary dispensation from the Catholic form if he or she intends to continue in the practice of the faith and religion.
Be supportive of your child.