Hi david is right. It sounds fairly large. This being the case - ideally the treatment is surgery, including a neck dissection where a minimum of 28 nodes are removed - ideally more. If he comes back with clear margins, on the tumor, and clean nodes that could be the end but he should be closely monitored for several years. If there is anything like perineural involvement (which is possible based on the size and description of the tumor/lesion) or any kind of nodal involvement then they should radiate and possibly do chemo. microscopic cancer could easily be living in the nodes but cannot be detected on a scan because it is so small.

best of luck to your friend.