I would at least request that the drywall be installed over furring strips. This way, you would not necessarily lose a full 2", but rather more like 1", depending on drywall thickness.
The problem is that the drywall will absorb any moisture that is present on the block wall and will warp and/or mold - either way, a bad situation!
I think if he simply furs out the wall, he may not have to do anything with the door other than rip down the trim around it.
Good luck with your new house!
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