If you can show that faulty installation was the cause of the mold problem your parents could definitely sue the installer for damages related to mold, and possible to his health problems.
To prove negligence (negligent installation), you would have to show that the installer did not live up the ordinary standard of care for an AC installer. Basically, it is a case where if it was incorrectly installed through his own error, you would win. The issue is showing that it was installed incorrectly, and not that something changed over time through no fault of the installer, and that it did in fact cause the mold.
But yes, there is no reason your parents could not sue and win. The installer most likely has insurance to cover these things, so you shouldn't have trouble finding a lawyer to represent them.
Please rate my answer as one of the top three faces when you are ready- I cannot control the law as it applies to your case, this rating describeswhether my answer was correct (not that the answer was good news) without this I do not get credit for my time. If you are not satisfied with my response,please press "Continue Conversation" and allow me to address your issues. I only get paid credit for my time if you rate my answer positively, I answer these questions on the honor system, please do not abuse it.
I see. Yes, they might have a claim, but they would definitely need a doctor to agree that the mold at least contributed to the pneumonia problems. Again, if true, then yes, the company would be responsible. Even though you and I know that mold causes breathing trouble and pneumonia, you still have to find an expert to agree with that. That should not be too terribly difficult in this case. But if he has other problems or other possible contributors, that could complicate the issue.
The botXXXXX XXXXXne is that the key is getting a physician to go on record that the mold caused the health problems.
DISCLAIMER: Answers from Experts on JustAnswer are not substitutes for the advice of an attorney. JustAnswer is a public forum and questions and responses are not private or confidential or protected by the attorney-client privilege. The Expert above is not your attorney, and the response above is not legal advice. You should not read this response to propose specific action or address specific circumstances, but only to give you a sense of general principles of law that might affect the situation you describe. Application of these general principles to particular circumstances must be done by a lawyer who has spoken with you in confidence, learned all relevant information, and explored various options. Before acting on these general principles, you should hire a lawyer licensed to practice law in the jurisdiction to which your question pertains.
The responses above are from individual Experts, not JustAnswer. The site and services are provided “as is”. To view the verified credential of an Expert, click on the “Verified” symbol in the Expert’s profile. This site is not for emergency questions which should be directed immediately by telephone or in-person to qualified professionals. Please carefully read the Terms of Service (last updated February 8, 2012).