If there is a honey super on top, I would remove that prior to the move. Drive the bees down to the brood boxes. Divide and conquer. You could have extra bottom boards and lids on hand, separate them, at dusk, the night before. There may be some chaos at that point. The question is, would you seal up the entrances that night or in the morning? I can envision the queenless 1/2 migrating over to the other 1/2 that has the queen.
Location, location, location. That is an extreme location! It's not meant for old beekeepers. Is this his 1st year with hives in this location? If not, he has experience on how to get 'er done.