You're talking correspondence tournaments, right? I know unrated people can play in some, because I've had unrated people as opponents in my groups in some tournaments. But I think the only way to find the ones that will take an unrated person is to try them one by one.
A lot of tournaments require a small minimum number of completed games to enter anyway (5 games is common), and that's probably somewhere around the number of games you need to play before the first rating is assigned. So he could also just play a few non-tournament games and that would solve both criteria for future tournaments.
Hey, everybody I have a new friend here and he can't find any tournaments to play in. He's unrated right now and I want to know if there are any tournaments he can play in. Thank you all in advance for your help.