Yes, it’s never mentioned. My fanfic story of LBT 17 does though. In that one, it wasn’t the fault of Sharpteeth, but a fight between Cera’s dad and other Threehorns that went wrong, leading to falling rocks landing on Topps’s family (or most of them). In my story though, Topps had a living 25 year old daughter named Olivia, but she decides to live in the Mysterious Beyond and marries a Threehorn named Charger and they have two kids: Dana and Dinah.
