Yes. You need an online account created just to even play singleplayer. Creating an "online account" for BF2142 requires you to have internet access because the game is going to register the account to the game (or even lock the CD-Key to your online account). So if you can't use an internet source somewhere else for your PC, you might as well return the game to the store.
I also recommend downloading all of the patches for BF2142. The latest patch is 1.5.1 I think. I think you can download the patches from the game (unless your friend has crappy DSL, it'll take HOURS to download the patches). Patch 1.5 I think was either 1 or 2 whole gigs. Anyway, either way, you'll need the internet.