I would NOT wash the blocks either before or after. Since they are from your husband's " great great grandmother" they are very old and probably very fragile depending on the fabric.
I agree with Ramona Byrd--the owner should contact a museum that handles old quilts or clothing or a quilt appraiser in your area to find out the best way to deal with the blocks.
I have a quilt top from 1870 and was advised by an appraiser that due to the fabrics used and how fragile they were, she recommended that the top not be quilted because of the added stress put on the brown fabric.
While it would be nice to have a textile from your husband's family to pass down as a quilt, sometimes it does more damage because it accelerates the decaying process.