Does your client have a Gear VR or rift? Or you were talking more of a realtime app? If your client has a rift, good chance he has a decent gpu to run your .exe!!!
The closest thing you could do, that would run on mobile, is a 360 pano that works well with the phone’s gyroscope. As you can see here http://littlstar.com/photos/d856ba1a
It could even be in stereo mode for gear vr on mobile if you do it with vray (not sure if blender can generate stereoscopic render)