As for Nate, Jacob, and the other people that had stayed on the first floor aside from Ferman's wife and son, they all went to help install the generators for their electricity, which were mainly for the aircon and lights in the mansion, and then arranging their connection with solar panels outside.
From the conversation from Nathan and the others, apparently the mansion also had solar power installed before, but they had just taken them down to change them to newer panels that have appeared, and the old ones were taken back by those that they had called for removal, and they had just been waiting for the arrival of the new panels to be installed.
They had apparently taken advantage of the weather before the apocalypse to replace those panels, as they weren't being used yet because of the gloomy weather in the area.
