He’s just suggesting you to put a “dark mesh” on top of everything in your area, and fade it out based on camera distance
If you do that you still get the skylight back when you get close. But then when you detect you are close you could dim the skylight. The point of this trick (or the one suggested by Epic in their livestream lobg ago) is to smoothly fade the skylight out (until its completely off) when you go indoors and fade it back on when you go outdoors. Of course looking out through a window would break the effect, and the transition needs to be slow enough for the player not to notice
At this point if you’re using dynamic lighting there is no other way to solve it though