Find my friends iphone

Have him use any internet browser and log into www.icloud.com/find with his Apple ID and password.

Also see the following Apple articles for information about lost or stolen iPhones or iPads: If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support and

Use the Find My app to locate a missing device or item - Apple Support

Not sure if your friend really wants to give you their Apple ID and Password. Are they willing?