Canadian resident working abroad for U.S. company

I've been asked to assist a Canadian resident who is working for a U.S. firm in the Middle East. As I consider the various resources that I should be bringing to the situation, I need to confirm that my thinking is correct... as a Canadian resident (undisputed, as he returns to Canada every 28 days for 28 days, then returns to work) paying Canadian taxes, is the fact that his employer is based in the U.S. a material issue, seeing that he doesn't work in the U.S.? Any issue with the location of the job (Middle East) or that he's paid in U.S. funds? Just trying to clear the smoke so that we are confident of what facts are material and which ones are red herrings. I'd appreciate anyone's comments. Thanks!

the fact that the employer is a US company only matters in the sense that the employee can never qualify for the Overseas employment tax credit (if he were to work outside canada on a longer-term basis), but it does not open him to US taxation if that is what you were worried about.

Thank you for this insight! This does resolve a primary question...with no accountability to file a U.S. tax return, I can help him with the same planning options as a "regular" Canadian taxpayer. Thanks again for your help...