Texas has (quite ironically) pretty strict rules against open carry, and there are stories told around the gun counter that if the wind blows your shirt open and exposes the gun you'll be hustled off to 40 years of hard labor or summarily executed.
Fortunately, that seems to be a bit of hyperbole and you have to be pretty deliberately openly displaying the gun to get in actual trouble. (But seriously...call your reps and get your open-carry situation fixed, ok? That's a real embarrassment for the great state of Texas to endure!)
For some folks, it takes a lot to really get over their social conditioning that carrying a gun is somehow an anti-social, dangerous, and illegal thing to do, and their fear that anyone who ever notices it will bring about the end of life as we know it.
Time fixes this for almost everyone. Carrying the gun daily, or as often as possible, wears down that blush of unfamiliarity and helps the new 'toter to relax.
Always remind your friend that the more he messes with it, the more likely someone IS to notice it, so get him to keep his hands off of it.