Welcome to the Community Forums, thanks for your first post.
I'm sorry to hear you're having trouble connecting your Son's Xbox to your home network. Can you please confirm if you have tried factory resetting the hub? If not, to do this you'll just need to stick a pin into the pinhole at the back of the hub for 30 seconds. Once the hub is back online, can you please try and forget the network on the Xbox and reconnect to the WiFi? Just make sure that the password is also definitely being put in correctly 🙂
Have you also been able to try connecting the Xbox to the hub via ethernet cable just to see if you're able to connect to the internet that way?