This is from DS and TV week Aus
Tom Fletcher, Sally's foster father, will return from the grave. It's not been confirmed that he's coming back 'alive'. Rumours suggest he will appear as a ghost/figment of Sally's imagination
Milco's true identity is revealed today in Oz today, and Tom's reappearance occurs next Monday.
Rumour is Sally flatlines next week in the wake of Johnny Cooper's attack (he's escaped from jail) so I assume that is when she 'sees Tom' This is also just after Miles' revelations about who he is so assume it's all tied in that way.
EDIT: Rumour on DS is that Milco is Sally's twin