How does it fail? The Indian Army was able to wrap things up in under a week IIRC, even if the Hyderabadese (Hyderbadi?) forces are able to beat them or at least force them to a draw India has a much larger armed forces and can just keeping throwing Brigades at them until they're beaten. The only way I can see this working out would be that you'd need an outside power backing Hyderabad that was powerful enough to get the Indians to back down. Even then Hyderabad is completely surrounded by Indian territory so the can simply blockade, either fully or just commercially, them in the aftermath. You're best bet would be if at some point in the past they had managed to gain a chunk of territory that gave them a coastline, that at least might make them a viable state.