Answer
Based on official Jordanian legal texts
After the father's death, the default under Jordanian law is that the mother is most entitled to custody of her children, since Article 170 of the Personal Status Law places the biological mother first among those entitled to custody, and custody does not pass automatically to the father's relatives merely on his death.
Custody, however, is one thing, and guardianship over the person and funds is another. On the father's death, guardianship over the minor's funds passes to whoever the law specifies in the order of guardians in Article 223 (the father, then his appointed trustee, then the true grandfather), or to a trustee chosen by the court; Article 230 addresses appointing a chosen trustee by the father or a court-appointed trustee to manage the minor's affairs.
The child's day-to-day care thus remains with the custodian under the order of Article 170, while the court organizes guardianship and trusteeship over his funds in a way that preserves his interest.
Assessing who is most suitable for custody and appointing a trustee remains within the Sharia Court's competence on the facts of each case, with regard to the child's best interest.
This is a general explanation based on Jordanian Personal Status Law and does not replace advice from a qualified lawyer in a specific dispute.