You learn that a close friend is successful because of illegal activities....

[Annoying]

Would it change your relationship? Would you tell anyone else?

[Mr. Noodles]

It'd depend on the specifics.
Let's say one of your friends sold cocaine.

[Annoying]

I liked the serial killer one better.

[Annoying]

But it would matter of what he/she did.

[killer_queen]

of course it would. i don't think someone like that be a good friend.