Either direction doubled will still result in doubling his area (40 Sq feet). So if 4 feet is his "width" then the new "width" will be 8 feet. Now if he doesn't have room in his yard to double the 4 feet to 8 feet, he can double the 5 feet to 10 feet and still end up successfully doubling his...
The seller may have had an emergency that took them out of town. Maybe their next dropping off point has finagled on them creating a domino effect. At any rate, you have a few options. Perhaps you can talk to your current landlord and ask them if you can rent the next month out of lease while...