A few more specifications would be of great assistance in getting you a meaningful answer. For example, where is your friend's site hosted? Is it local to him or with a hosting company? What are you hosting? WMS? WFS? Tile-Cache? How are you hosting it? Local development box? VM? Web accessible server?
Blind guess assuming you are not serving a lot of data, you are on a good connection, your friend is not picky about styling, and your serve is both secure and web accessible:
The short hackish answer would be to send him an html page with full urls to whatever layers (WMS, WFS, WCS) that you want to serve. He would need to have openlayers and any other javascript libraries you are using installed local or again, provide full urls so that he can hit your copies. He would not have any control over the layers being served or their styling, you would be serving your application, from your server, to his users. He would just embed the 'service' into his site.