He cannot come back. I have a friend who happens to be my officemate also, with the same case like your friend. He was deported 2007. He was ban in qatar but not to other GCC countries. Ban period for deported person is not the same case like when you exit, resigned, or cancelled, you will be blacklisted. The company gave my officemate an NOC both english and arabic, but its useless because he was blacklisted already. Maybe for pity sake only thats why they gave him an noc, and they know also that it will be useless. He renew the passport, so the passport number will be change, tried to apply for visit visa, business visa, and family visa, but still it was rejected, reason of embassy, he was blacklisted to qatar.