It sets 7700 and broadcasts what's happening, incapacitated pilot is an emergency so that's what it will tell everybody. If there's a controller on frequency it's up to that controller what to do about it, but there's no use arguing with a machine and the pilot is incapacitated, so my expectation is that a controller will keep other traffic out of the way, and if the autoland has picked somewhere with a local tower they'd call that tower and give it heads up it has got an incoming emergency, expect to close the incident runway while they clean up the aftermath.

Regardless, the machine will be broadcasting its intentions and again, there's no arguing with a machine other pilots will just have to accept that it's intending to land and stop on the runway putting it out of use until further notice.

Since the machine can't see lights, I assume it doesn't care whether they are functioning. So in the dark it's likely to land at some small airfield which is actually closed, slightly scary for the passengers to just come to a halt in darkness far from anywhere but arguably safer since nobody else is going to make the error of landing when the runway remains occupied.