We haven't done a character call for a couple of years now, but I'm certain it mentioned the destination and maybe the ship. Other than that it was a "canned" call (no mention of names, dates, etc.). However, there was a thread not too long ago and people reported the call was very generic without mention of the ship, the destination or anything else identifiable.
DD absolutely loved it! The next day she got everyone at school excited because Mickey called her. Your son should enjoy it, but if he isn't expecting a cruise he may not realize what it's about, and it's a fairly short call.
Enjoy your cruise!