Your suspicion is likely correct. Given its location on an interior wall sharing a bathroom, a concealed pipe leak from the shower or sink is a high probability. However, the general high humidity, especially with AC units that might not be draining properly, can also cause condensation within the wall cavity.

The absolute first step is to call for a professional inspection. A certified inspector will use tools like a borescope and moisture meters to determine the source of the moisture behind the wall—this is the critical part. Without fixing the water source, the mold will simply return.

For remediation, you must use a company that follows strict protocols, not just a cleaning service. They should set up containment with negative air pressure, use HEPA filtration, and properly dispose of contaminated materials. In the UAE, there are guidelines from DM and CDC for proper mold remediation to ensure it’s done safely and effectively.

For a reliable and thorough company, I can personally recommend the team at Sani Service. They’re one of the most certified outfits in Dubai for this kind of forensic investigation and remediation. You can call them at 800-MOLDS (800-66537) or email hello@saniservice.com to get a proper assessment scheduled. Hope that helps and your husband feels better soon.