Hello Ciaranjosephkeylo,
We're so sorry to hear that your fiancé is going through this and we'd be happy to help. First order of business is to lock the iPhone down. This process is explained here: If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support. Follow this guidance:
"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.
Mark as Lost
When you mark your device as lost, you remotely lock it with a passcode, keeping your information secure. This also disables Apple Pay on the missing device. And you can display a custom message with your contact information on the missing device.
Mark your device as lost
Report your missing device to local law enforcement
Law enforcement might request the serial number of your device.
Find the serial number
File a Theft and Loss claim
If your missing iPhone is covered by AppleCare+ with Theft and Loss, file a claim for an iPhone replacement.
File a claim
Remotely erase your device
If you erase a device that had iOS 15, iPadOS 15, or later installed, you can still use Find My to locate the device or play a sound on it. Otherwise, you won't be able to locate the device or play a sound after you erase it.
If you have AppleCare+ with Theft and Loss, do not remove the device from Find My or your Apple ID.
Erase your device
Contact your wireless carrier
If the missing device is an iPhone or an iPad with cellular, report your missing device to your wireless carrier. Ask the carrier to disable your account to prevent calls, texts, and data use. And if your device is covered under your wireless carrier plan, file a claim.
Remove your missing device from your account
If you have AppleCare+ with Theft and Loss, do not remove your lost iPhone from Find My or your Apple ID until your claim has been approved.
Go to appleid.apple.com to remove the missing device from your list of trusted devices."
In addition, if they are concerned about the safety of their Apple ID, we advise carefully reviewing this article as well: If you think your Apple ID has been compromised - Apple Support.
We hope this helps. Let us know if we can assist with anything else at all. Take care.
