True, I also kinda liked the truck part. I mean, at this point Isekai Truck-san is a trope of its own, more like a nod to the audience than anything else. Here, it gains additional flavor because her past trauma was the thing that brought her to death.
As for her brother, I don't necessarily think that some kind of sexual abuse was involved. Violent, controlling and oppressive presence of a close relative is more than enough to cause this, even without the... touchy stuff.