You should get more material first before you go out on the streets. Learn a lot of sleights and tricks, then practice hard until you feel confident enough to go out on the streets.
NO! He shouldn't. He should stick with what he has now, and PRACTICE what he has.
Mini Magician, master what you have now, perfect everything until your comfortable with all of your material. Perform on family, get a feel for performing for people. Friends and family are great practice as it allows for you to test your presentation and performance. Then, hit the streets. It will feel weird at first wanting to approach a stranger. You'll get the normal fear of rejection, but that's the worst that can happen; for them to say NO. Then you just try again. It just gets easier and easier each time you approach.
I like to compare it to asking a girl out. When I ask a girl out on a date, I get this feeling in my stomach because I'm afraid she'll reject me. I'm a shy guy, VERY shy. So each time I approach ANYONE I don't know I turn red, or start shaking. But hey, I've gotten used to it and have learned how to look past it. I can tell you though, approaching a spectator for magic is 100x less hard than asking a girl out.
When you say "illusions". Do you mean LARGE scale illusions? Because it would be hard to perform a metamorphosis on the street after approaching a stranger. So work with what you have, once you master it, test it on spectators, then hit the streets. When you are ready for more, purchase a book or two. You won't regret it!
Mitchell