Yep I agree with above. It does not matter if he believes. In the big scheme of things it is hard to prove anything to anyone.
3D heli's are simply amazing. The vid's are not faked and in fact the heli's do what you see. They are talented pilots using top notch equipment and the advances in systems have enabled what you see.
The Gyro's, and CF (spell that stiff) blade and fast head speeds enable what is done. A full scale heli spins at 200-300 RPM these at 10x that.
Not sure where you live but I'm sure he could get a "live" show at a nearby club and be convinced. But in the big scheme of things - that just isn't all that important!