Did I miss something? How do you guys know his snake is pooping fine?
RU, your snake should probably poo about once a month or so, although once every six weeks isn't uncommon. It depends on the age/size of your snake, feeding amount/frequency, and activity level of your snake. It is possible for snakes to become constipated, but if he is going once a month or so, you most likely have nothing to worry about. You could always take a sample to a vet and have it checked for parasites, if you are concerned about that.

New snake keepers are often baffled at the length of time their snakes can go in between offloads, so we typically tell them to calm down and wait it out.
If you want to "encourage" your snake to poo, a lukewarm bath (75-80 degrees) for an hour or so will usually facilitate a load dump.