The younger Cuenco said that his father experienced "mild fever and incessant coughing" on June 18 which prompted them to conduct a swab test and later showed on June 20 that the elder Cuenco was positive from the said virus.
The information provided describes how the elder Cuenco was diagnosed with the virus after experiencing fever and persistent cough on June 18th. The younger Cuenco's account of his father's symptoms prompted a swab test, which confirmed the diagnosis.