Snowy, a ghost, is able to walk to what mortals regard as the end of time because his backwards-forwards dimension corresponds to their temporal dimension. Walking along a corridor above the mortal realm, he is able to look down through apertures at cross-sections of some of the world lines in that realm. It follows that Snowy's temporal dimension is at right angles to the temporal dimension of the mortal realm.
Although the last mortal dies a long time before the end of the universe, Snowy continues walking until he reaches that ultimate end. If he were to converse with the last mortal, then he would have to:
interrupt his "futureward" hike;
descend through one of the apertures;
rotate through ninety degrees so that his temporal dimension became the temporal dimension of mortals.
He would then be able to converse with a being who would otherwise appear to him as one end of a static world line.
The corridor along which Snowy walks is the lowest part of an "Upstairs" realm inhabited by ghosts and angels. Some of the angels have either fallen or been pushed down into a demonic role but will eventually regain their angelic status. But surely this "eventually" is in the far future of the temporal dimension of the "Upstairs" realm which is at right angles to the temporal dimension of the mortal realm? Snowy should not find a demon transformed back into an angel waiting to converse with him at what mortals regard as the end of time. This "end of time" is not the end of time for angels but is merely a remote point along one of their three or more spatial dimensions.