Thank you for all your responses, I have now found out the router that he is using, which is the GRV9517UWAC34AOT. As a result of this information, I was able to find a nice video from Plus Net, showing how to log in, and set up your own WiFi details. Hopefully once he has seen that, he should be able to work out how to disable SIP ALG, to see if that would get the ATA working. If that does not work, I will have post him some information from one of my old routers, on how to set up port forwarding. But I hope that I won't need to do that.