Unfortunately, he may be being offered less simply because he is of Arab origin. Racism is alive and well in the GCC - and although he holds an American passport and is an American citizen - his "name" might be lowering the offer someone else with the name of Smith or Jones might get with similar qualifications and experience.

I don't know what position he is going for or his education or experience but I would say 18000 is low - very low if he is an American university grad with a degree in engineering or similar. I don't know about being paid double his US salary though - one big advantage is there is no income tax here (but I understand US citizens do have to pay some US taxes if they earn more than a certain amount outside the US)

Be especially careful about education allowances for children - is it per child or a set amount for any and all children? Schooling can get quite expensive here depending on where you send your child - and the American curriculum schools tend to be among the highest - they also have long waiting lists, you won't be able to just drop in and register the same day.

55000 for the furniture allowance is not bad, be aware that furniture here is not of a very high quality (how I long for IKEA - at least it's fairly sturdy for the price) and tends to be overpriced for what you get IMHO.

Hope that helps