It's sad, but to be kind of fair she hardly has any scenes in general. The aunt that got a scene a couple of updates ago has about the same amount of screen time as the mom, but is much more open to incest, so it would kind of be weird for the mom who's been shown to be fairly averse to that sort of thing to get a scene first. It seemed like it took ages to build up to a proper scene with the reticent sister, and it's probably going to be a similar wait once the mom starts getting a reasonable amount of screen time again, maybe even longer. Idk what the dev's plans are, but I'd guess based on the reluctant sister's timeline that it'll probably be at least three more updates before something noteworthy with the mom