There is no rule stating you cannot create an account for someone. There is not even a rule for having multiple accounts.
There are several prominent account creation services on the blockchain. Steemit Inc. and @blocktrades being the most notable. Other ones include @someguy123's AnonSteem. You could also ask @guiltyparties or @netuoso for such services as well. Even @utopian-io offers account creation.
In fact, if you have the RC and tech savvy enough, you could make your own accounts. I have gotten a few from my friends.
Since you are making one for your friend, it would be a perfect time for you to teach that person about Steem. It will be a great opportunity.
Just do it. Spread the STEEM!