He was Muslim, then he went back to his country and apostatised, then he came back to a Muslim country; is he a mu‘aahad (non-Muslim living under Muslim protection)? How should we deal with him?

No File Exists
Check below answers in case you are looking for other related questions:
He became Muslim then he left Islam
Marrying an atheist woman who became Muslim, then apostacized

No File Exists
Related Answers:
Reviling the Religion of a Muslim
He did not fast Ramadan and he thought negatively of Allah, may He be exalted
A Muslim apostatised and became Christian in order to get asylum in a foreign country, but he believes that he is still a Muslim
He became Muslim then he left Islam
Marrying an atheist woman who became Muslim, then apostacized

Recommended answers for you:
Meaning of the word Pokemon
Ahaadeeth about the virtue of sadaqah (charity)
Is it permissible for husband and wife to remove their clothes when sleeping? What effect does that have on tahaarah (purity, cleanliness)?
The difference between maniy, madhiy and moisture
Will children who die young go to Paradise or Hell?