Did he remove the stucco, and thereby the mold, because of the mold problem? Or did he just find the mold after removing the stucco? Did anyone in the household get sick because of the mold ? As Pool Cleaner said, medical expense route should be researched by you. Found this, which may or may not be similar to your case: Lead-based paint removal is deductible if done for a child who has, or has had, lead poisoning from eating the paint, Revenue ruling 79-66. Also under medical expenses defined per US Master tax guide 2021: medical expenses eligible to be claimed as an itemized deduction, code 1015, include amounts paid for the diagnosis, cure,  MITIGATION,  treatment, or PREVENTION of disease. Hope this helps and just my opinion