As a resident of Uptown New Orleans, I open carry very infrequently. Mostly in front of my house, in the yard, and on quick trips to the corner store, etc. When exiting my vehicle while open carrying in the city, I always do a quick head check for police, because I have no doubt that New Orleans finest (worst) would not hesitate to take me down, cuff me, lock me up with the animals in OPP, and ask questions later. It sucks, because it makes you feel like a criminal for exercising what should be a very clearly-defined right in this state. However, having lived in Washington, I can tell you it is the same way up there. Open carry is (mostly) cool throughout the state, but you have to have some real cajones to do it in downtown Seattle.
My advice: tell your friend to do everything he can to get a CCL, carry in his vehicle at all times, work to get the NOPD and OPCSO to recognize a basic right, and open carry using only his very best judgment.
EDIT: As far as people's reactions, I have found them to be either a) positive, b) surprised ("Damn, he got a pistol on his hip!"), or c) non-existent. I have not personally encountered negative reactions.