Is it permissible for a Muslim parent to enroll their son in boy scouts? Muslim boy scouts are not available in his area.

Praise be to Allah, the Lord of the World; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
Every Muslim who lives in a non-Muslim country should leave it for the saying of Allah "Verily! As for those whom the angels take (in death) while they are wronging themselves (as they stayed among the disbelievers even though emigration was obligatory for them), they (angels) say (to them): "In what (condition) were you?" They reply: "We were weak and oppressed on earth." They (angels) say: "Was not the earth of Allâh spacious enough for you to emigrate therein?" Such men will find their abode in Hell - What an evil destination!". [4:97]
The above verse revealed mentioning some Muslims who did not migrate from Makkah to Madinah. The Prophet also said: "I am not responsible for any Muslim who stays among polytheists". [Abu Dawood and Tirmizi] For more details, please read the Fatwa:81464 and 81642.
As for permitting your child to enroll in boys' scout we advise you not to let him join such scouts since a person learns much from his colleagues. No doubt that the non-Muslim friends will have very bad impact upon his religion. The Prophet said: "A man follows the religion of his friend. So each one should consider whom he makes his friend".
Allah knows best.