There's a lot that needs to be answered before anyone could answer your question with authority.  His new employer would be best to tackle any issues before he gives up his current job and visa. They would know best.

I can think of one possible hurdle... it all depends on nationality. I've heard that there are quotas or restrictions on visas granted to nationals of certain countries. A while back, I think many Jordanians were having trouble getting the visa approved --- because of political issues between Qatar and Jordan.

Again, I think it's best for your friend to check with his new employer. If it's a major oil company, they should have a professional Immigration/HR staff.