Sorry, fixed the link; I had copy-pasted from my response to your same question on the steam forums and it ate the link.
All the instructions are in that thread, although he may have to consult his router instructions since he's hosting. If it seems set up correctly but it still doesn't work, then 99% of the time one of you has a software firewall that isn't allowing AI War to talk through. Sometimes antivirus software has that built in, like I mentioned; but there's also the regular old windows firewall, standalone software firewalls like ZoneAlarm, and so on. Sometimes you can have multiple software firewalls running at once; some third party firewall and the windows one, usually.
Very rarely, mainly at certain college dorms or similar, you might find your traffic is barred from the network based on being an unfamiliar port to the network. In that case you could both switch the game to using a very common port, like port 80 or something. If both of you are using the same port, then that's going to work fine to change it; but you'll be unable to connect to anyone else using a different port unless you change them back later.
If worst comes to worst, there's always Hamachi and Commodo and similar. Those bypass both strict college dorm network restrictions, as well as the need for port forwarding. Sometimes they bypass the software firewalls, but usually not; if you still can't connect AI War even with Hamachi successfully connecting your computers, then you're pretty well guaranteed it's a software firewall that someone is missing.
Hope that helps!