When I moved Lolli, I think the biggest help was to set up her area in the same exact way as possible. I set up her pen the same way at my dad’s the same as I always had it. I also think restricting their space will help. Even if they will eventually have a whole room or free range, allowing them a confined space doesn’t overwhelm them and makes them feel safer. And even if you aren’t able to set up their full living space at your boyfriend’s parents place, keeping some things the same will help. Like keep their litterboxes, bowls, and toys in the same general spots at the new space as where they currently are.
As we know, rabbits are creatures of habits. Lolli never seems to mind when her things change places. A lot of times, she moves her stuff around. lol So she handled moving to my dad’s fine. Just remember that they might get stressed and be grumpy with you, but they really are fine.
Good luck! I would be soooo scared if I had to deal with hurricanes!