My nephew microwaved phone and phone network and wifi is not working

Tabish Jaffri dang if the only thing that’s not working is the WiFi, your are lucky. Anyhow, because of having gotten microwaved, you would need to take a look at the circuit board and see if there is any damage to it. It is possibly that this is a destroyed WiFi IC, a destroyed antenna or destroyed components in the WiFi circuitry. You can check for visible damage but ultimately this will most likely require some board level repair. Post some pictures of what this all looks like if you are going to work on it. that way we can see what you see and “maybe” help you out further. Use something like this video to work on it and this Adding images to an existing question to post your images