Ask your friend to call qatar embassy in UAE and tell them about his craft and ask them that whether he can get visa on arrival or not. Some crafts do get visa on arrival (GCC residents only) like engineers, doctors and lawyers etc. I dont know about the complete list.

I am an engineer and when ever I go to any GCC country I get the visa on arrival at airport or on border if I go by road and I have gone to UAE, Bahrain, Kuwait and Qatar in the same fashion.