Does the Alphard work as a 4WD on rough ground?

Apologies if I’m showing my ignorance here but I don’t fully understand the 4WD nature of the 2008 Alphard 2.4l Hybrid.

I had assumed that there would be a knob to switch on the 4WD. However, I now understand that it always has electrical drive to the rear wheels as well as the petrol drive to the front wheels, hence four-wheel-drive.

So my question is, will it function as a four-wheel-drive if the front wheels can’t grip, in mud for example?

The reason for my question is that I have a regular journey across about ¼ mile of rough track which can be very muddy. My previous vehicle (a 2 wheel drive, Toyota Granvia) sometimes struggled.

Any advice appreciated!

Ian