What is the right to custody of children after the death of the Muslim father if the mother is Christian and the Muslim relatives are very distant?

Custody and care of children may not be given to a disbeliever. If it is not possible to send the children to the husband's distant Muslim relatives, then they must be given to a Muslim family for their care. The conditions for a custodian are: Islam, sanity, puberty, and good upbringing. The reason a disbeliever may not have custody of a Muslim is that the custodian strives to raise the child in their religion, and because custody is one of the strongest causes of allegiance, which Allah has severed between Muslims and disbelievers.