I need help finding my son's iPhone

Is the Find My feature turned on? If so, you can log into your son's iCloud account by visiting iCloud.com. Once you're logged in, you can use the Find My service to locate the device or view its last known location.

Look for your device on a map

To find your device, sign in to iCloud.com/find. Or use the Find My app on another Apple device that you own.

If your iPhone, iPad, or iPod touch doesn’t appear in the list of devices, Find My was not turned on. But you can still protect your account if Find My was not turned on.

Once located, you should immediately mark the device as lost. See the Apple support article below for more details.

If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

Best of luck finding your son's device.