Your situation could be caused by a number of things. I would first open open Network Connections, disable the network adapter, and re-enable it. If that does not change anything, open a CMD prompt and try to run "ipconfig /renew". If that does not work, you may have a bigger problem.
From the laptops perspective, it might be hard-coded for a static IP if he requires one at home. From the routers perspective, you may have a MAC Address White-list which is preventing non-specific PCs from connecting to the network.