Two things, kabuto said he needed a living Uchiha - not Tobi...
Second point, Kabuto is loyal only to he old dead master's dream which was living forever or bring the dead back to life with something more powerful that the edo jutsu. If he could bring anyone back to life with immortal powers it would be Orochimaru. He is by far the most dangerous villains in the Naruto story. You just watch, Orochimaru will come back, take sasuke's evil body, destroy Tobi plans, become immortal, and only the child of prophecy will be able to stop him.
Plus he make evil look better than Tobi anyway.
Second point, Kabuto is loyal only to he old dead master's dream which was living forever or bring the dead back to life with something more powerful that the edo jutsu. If he could bring anyone back to life with immortal powers it would be Orochimaru. He is by far the most dangerous villains in the Naruto story. You just watch, Orochimaru will come back, take sasuke's evil body, destroy Tobi plans, become immortal, and only the child of prophecy will be able to stop him.
Plus he make evil look better than Tobi anyway.