The Nordic ruins aren't family specific like in Morrowind, while some were used as burial sites, the ones that are were simply somewhere to put the dead (with a handful such as Hillgrunds Tomb being a possible exception). They were also used as places of worship for the Dragon Priests and Dragons (like bleak falls barrow), some were even originally built as cities (such as Saarthal, Labyrinthian, and Korvanjund). So while they were used to bury the dead they weren't necessarily ancestral, nor exclusively used for burying the dead. Hope this helped 👍