Annotated 41-3
Panel 3 here calls back to Captain Hookeye and Mr. Glee, the pair of ghosts Gravedust raised and avenged in his (chronologically) first adventure with the soon-to-be-Peacemakers.
Panel 4 does not refer to any one moment we’ve seen, but it does encapsulate a lot of Frigg and Gravedust’s scenes together, especially in Chapters 13 and 27. Frigg giving Gravedust an aggressive eye-roll is just Frigg being Frigg: the fact that she’s listening to him at all is the accomplishment here. This relationship of theirs won’t be as visible in chapters to come: Frigg is starting to outgrow the need for father figures… but one of the reasons for that growth is that Gravedust has done his job as one.
Panel 5 shows Gravedust’s recent failures: a spirit he failed to avenge and a woman whose spirit he failed to save, leading to the destruction of both and doubts about his life’s purpose.
That’s a good point in regards to father figures (any parental figure really). If you get to the point you stop looking for them, it’s likely because somewhere along the way you found one and it did the job. The toughest thing about parenting is that your job is to make yourself unnecessary.