A whole different issue comes into play if you are on cable internet since a lot of time cable internet providers have dynamic ips.
If he doesn't have a static ip, it introduces another fun element.
Seems like what you said about at least a basic migration to a different port makes since.
Druff in WHM it is something like /etc/ssh/ssh_config or sshconfig or ssh-config you should be able to Vi in and change it....make sure you update your Firewall first.