
I'd sight it in at 25- even if you only practice and shoot 5, 7 or 10yds. Primarily then it will be GTG at any distance he's ever going to shoot that gun.
We all have our preferences, I shoot my little PF-9 to 20yds when I shoot it... walk 20 steps and see how close it is... your gun will shoot decent groups at that range. (you just have to learn to drive it) I've had to dispatch animals at that distance a number of times.
Just don't pigeonhole yourself to be an arm's length shooter.
