The following sentence is from the Constitution of Japan (Article 26).
すべて国民は、法律の定めるところにより、その保護する子女に普通教育を受けさせる義務を負ふ。
The English translation (or rather the original text?) says
All people shall be obligated to have all boys and girls under their protection receive ordinary education as provided for by law.
So the "その" in bold font means something like その人が. Is this a standard usage of その?