Bluetooth connection

All she has to do is follow the instructions to connect the iPhone to the car. As long as the pacemaker is connected to Bluetooth, it will remain connected to Bluetooth. Connecting to the car is a separate connection and Bluetooth supports more than one connection. Follow the paragraph titled Connect Using Bluetooth. How to connect your iPhone, iPad, or iPod touch to your car - Apple Support

Pairing and connecting multiple Bluetooth devices on an iPhone is feasible, contingent upon the compatibility of the devices in use.

It's important to note that pacemakers and medical devices have specific guidelines and recommendations regarding the use of electronic devices, including smartphones and Bluetooth. It's crucial to consult with your wife's healthcare provider or the manufacturer of the pacemaker to ensure that using Bluetooth devices, especially simultaneously, is safe and won't interfere with the pacemaker's functionality.

If there are specific concerns or restrictions related to the pacemaker, your wife's healthcare provider will provide the most accurate and personalized guidance. Safety and health considerations should always take precedence in such situations.

So, I can have mine connected to my Apple Watch and my vehicle. Have you checked with your physician to see if there are any restrictions on the pacemaker's connection? Have you ever paired the iPhone 14 to the vehicle? Did you try the steps for that? If she has an Apple Watch, it should have paired to that when the Watch was activated. Does the Watch appear in Bluetooth in the Settings? Is this a new (to her) iPhone? It should always remain connected to the Apple Watch once it has been paired and the Watch is on and within range.