Sorry to hear of the issue.
What the buyer of your home is after, is a statement from the person who put up
the dry wall, whether the new wall was a show and tell.
Hence if a licensed contractor put it up, then you are covered.
If you put it up, then we get into a grey zone, that you put a dry wall to hide facts
and sadly will loose.
Inspections are great, but as they are not invasive , i.e. one does not drill a hole and drop
a fiber optic camera, as owner will generally not allow it, but inspections inspect show and tell.
A Mold inspection should have been done.
Also, if the new owner talks to your old neighbors there can be an issue if they say:
Hs and Kuhler always had water issues or we always had water issues in the nieghborhood, then you have a problem.
Good luck, may be get an attorney, or ask your agent.