maybe he has a twin brother in another city and they both go to the same fat camp. It's called 'The Simpsons' not 'comic book guy' so we don't know everything about comic book guys life.
stop coming up with ridiculous scenarios, the reason theres two CBGs is because the animators for the Simpsons are really lazy and they always repeat characters, even dead ones, they do it just to fill up the spaces and because we're not supposed to be looking at them anyway we're supposed to be looking at whatever is going on