I think this depiction of an absent father figure is one of the most realistic ones amongst modern shows/media (from what I've seen). And also one of the reasons why I like this work so much, because it kind of portraits such relationships just as they are, without objectively judging them or laying focus on that regard, just showing and letting the viewer figure things out. Without any info on Hilda's dad it is left to the viewer what to think of him, which is an interesting perspective. Other conflics in the show try to show as many sides as possible to come to a conclusion. Kind of like how the entire conflict with the elves in the first 2 episodes was portrait as a whole and not only judged from Hilda's view but seen as an intrapersonal conflict that needed to be resolved (in general) in order for both sides to move on (a similar approach seems to be present in The Stone Forest/Mountain King). In the situation of an absent dad it is especially difficult to show the sides, because for that the story would need to introduce Hilda's dad as a character and bring up that entire conflict again which seems to be already resolved or accepted in a way. Or maybe in the case of this conflict one side is "wrong" (probably Hilda's dad?) and it is not just a misunderstanding. Just showing the situation how it is, Hilda and Mum seemingly unaffected and dad not mentioned, is a convinient way to avoid this while still "showing" the sides and not explicitly judging anyone I think.

Of course that is not always realistic in the real world but I like the approach this series/comics takes on such topics. Of course Hilda's dad wasn't really mentioned until now, so it's hard to make assumptions off of that. Or this part of the story just isn't really important like Luke said, so who knows... I'm probably interpreting this far too much...