The wall of the daughter's bedroom is NOT insulated. Moisture from normal activities (showering and cooking) within the house are causing the realtive humidity to be above 50%. When that moisture enters the wall or ceiling, the temperature drops below the dewpoint and condenses out. The moisture that condenses makes a nice environment for the growth of black mold which is highly toxic. The mold will spread by airborne spores. If you have return air ducts for your HVAC system in the room, the spores might be dispersed throughout the entire house, depending on how good you HVAC filter is. Note that if you have a swamp cooler on the roof, it could be leaking water through the ceiling and causing the problem.
You need to immediately move you daughter to another room and remediate the situation -- tear out all the drywall and anything that is damp or has signs of visible mold. Get the humidity in ther house below 50% with a dehumidifier. I would recommend the Winix 50-pint model (refer to link below). This will condition 1500 square feet, which is a lot, but you will need one on each floor.
Amazon com Home Kitchen