Possible concept of a season 4 scene
So since >!the evil rich guy possessed Sandra!< >!and the ghost barrier is broken and we don't know exactly how Wally might get back to the regular afterlife or if he will bring Maddie's dad with there is a possibility that since Maddie can see ghosts Sandra Maddie's dad and Wally are ghosts!< maybe there could be like a really nice family dinner scene where Maddie introduces Wally formally to her parents it'd be so sweet