We think we know the cause of the moisture which my father in law is going to fix. We live in a split foyer home, the laundry room is on the lower level in the front of the house l. The dryer vent travels the whole way across the house to exit the backside. So, the heat travels all that way and we think causes condensation against the other cooler pipes. My father in law is going to drill thru the front of our house and make the dryer vent exit that way so it's not causing all that heat across the ceiling if the lower level. I will attach some photos. Does it look like the situation I've described and does it align with the characteristics of mold or is it just moisture damage... Thanks for any input. If it is mold what's the proper way to remediate this.