If your Apple Watch is dead and you want to find its last location, you can try it by following these steps:
1.Open the Find My app: Open the Find My app on your iPhone. If you don't have this app installed, you can do so on the App Store** and install it.
2.Sign in to your Apple ID: Sign in to the Find My app with your Apple ID. Make sure you're using the same Apple ID associated with your Apple Watch.
3.Select your Apple Watch: In the Find My app, you'll see a list of devices associated with your Apple ID. Select your Apple Watch.
4.Find last location: Under your Apple Watch options, you'll see the device's location. If your Apple Watch has previously set up location sharing, you can also see its real-time location.
Please note that in the above steps, you need to make sure that your iPhone can still connect to the internet and that your Apple Watch is using the account associated with your Apple ID. Also, if your Apple Watch is completely depleted, then it won't be able to provide real-time location information through this method.
If your issue has not been resolved, it is recommended that you consult through Apple's official support channels, and they will provide more detailed and specific guidance.