Beach With Dinosaurs

The Wellington sibs are having it hard. She's dying, and he's trying to cope. But then a madwoman from an alternate dimension enters their life, and soon enough dying is something they both do, but the adventure only begins there as they wake up in different universes. She meets Victorians of a sort, and a post-apocalyptic hometown, and he meets a beach with dinosaurs and literal space cadets. The first in a new series.