I found moisture in the attic during a home inspection today. How do I write the report without causing panic?

I performed an inspection on an older home today and found moisture stains on some of the attic insulation. The buyer got very nervous after seeing the photos. Instead of writing 'severe leak' directly, I first checked the roof penetrations, ventilation, moisture meter readings, and recent rainfall records. There were no active water droplets on-site; it looked like a combination of long-term…