Because it's a WIRELESS router and ADSL modem, it's only hooked into the phone line and mains eletric. All devices in the house connect to the internet wirelessly.
How to check the stuff on his PC... I'd guess and say if the setup hasn't been fiddled with too much, opening a browser and typing in
http://192.168.0.1/ for the URL should bring up the Netgear router config page. You'll need the login and password. In there there will be settings for DHCP and the like mentioned before. If there's any mention of MAC Address restrictions, turn that setting off, just to test it.
Also, you should be able to see Attached Devices, which gives you a list of the devices the router knows about and has allocated an IP to. If your Wireless bridge is there, then DHCP and MAC Address restrictions are working.