A lot of people do have a general idea that they're in a band to get big, though. They don't just play for the sake of playing anymore.

you can be both: you can love what you do and be ambitious about it.

Okay but you're missing the point of the post. You can be both, a lot of people aren't, though. Many young musicians play to get famous and not for the love of music.

true. but you also need to be able to be honest with yourself about what you really want from playing music and more importantly have the guts to project that honesty onto your bandmates.

Ask him if he's good enough to join you.