why does the i.f take ender back to earth?

Graff and the other officers of the International Fleet are running a delicate balance between pushing Ender to the edge and pushing him over it, and atthis point, Ender's reaction to his final battle at the school shows that he has finally been pushed over the edge. They really want to calm Ender down and let him decompress. It is interesting, therefore, that he wants to go back to Battle School when he gets down to Earth. He realizes that it is the only place that he feels truly at home, despite its being the place where he was ruined. His complete surrender at the end of his days at Battle School leads to his three-month landside leave, but it is not clear that Ender has anything back on Earth to return to.