Menuhax itself it's patched in 11.3. But not in 9.2. That's why he is using a SysNand 9.2 + menuhax + Emunand setup.
I helped a friend some days ago with this. She didn't changed to A9LH (yet, because laziness), but I managed to update her SD in order to work for 11.3.
She only had to change the boot.3dsx for the one from Luma, update the Luma folder, and delete any *.cfg file that was in the root of the SD(in order to delete the menu itself).
Maybe he has lesshax too, which would mean that he would need to change the menuhax payload to boot in "boot.3dsx" from Luma.