Yeah I'm not sure it works for Sierra. Oddly enough I have an old ASUS G72GX that I put El Cap on and the Fn keys work as they should without needing a driver
Trying to get this working on an ASUS ZenBook UX306UA (i7-6500U). Applied the DSDT patches, compiled with no errors. Installed the kext and then rebooted. Only thing that works is volume control Fn+f11/f12