Not an expert on drywall, but will probably have to be ripped out. Maybe someone else will comment.

The first pic looks bad but it's also very out of focus so it's hard to say. The other two don't look like a big deal to me. I'm not a drywaller, but I do have a couple of them in my family.

I think you need to look at why water is coming in, fix the problem there or you will always have an issue. It might be as simple as cleaning eavestroughs and making sure downspouts are away from house.

Sorry, didn't note it was not sided and finished. We had a similar issue when adding a second story to our house. Torrential rain caused water to pool on ceiling of main floor before everything was covered, sheathed. We did have good luck in that everything dried out ok but our ceiling (where the water dripped through) was plaster (not drywall).

I always thought modular homes were built inside and then delivered to the client and just minimal work to put together on site. I do agree this is not just a drywall problem there is wet insulation that needs to removed too.

Thanks all!

It takes more than a sprinkle of water to ruin insulation and drywall. It the area is protected and/or properly flashed so it doesn't get wet again, let it dry and forget about it.