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: