If she can connect the Apple Watch to the Hospital's WiFi network, then she may get more functionality, such as weather, and other apps that need access to the Internet.
If both the iPhone and the Apple Watch are connected to the same Hospital WiFi network, she may have full functionality, especially if (and there are a lot of "if"s here), her carrier supports WiFi calling, AND she has enabled WiFi calling on her iPhone, AND she has enabled WiFi calling on her Apple Watch, then she may be able to get phone calls as well.
If WiFi does not work out, then her distance from the iPhone is between 30 and 60 feet (9. to 18 meters), with the longer distance only when there is a clear line of sight between the iPhone and the Apple Watch.
If no WiFi and not Bluetooth, then the Apple Watch will tell the time, which can be useful for checking someones pulse, and it will track her activity (moving, steps, heart rate, O2 levels, etc...).