Abnur is currently 164 years old the Tharn faminly is one of the biggest Noble families of Cyrodiil. It's messy.waitaminute
As it stands, Euraxia Tharn is Abnur's half sister, but younger than Clivia. Javad Tharn is Euraxia's kid, but also allegedly Abnur's son and nephew? Septima Tharn is actually Abnur's daughter, but Abnur can't seem to recall how she's related to him in Heart's Grief. Though he had at least 16 daughters so I guess it's possible he could have forgotten.
Dang I'm confused.
Either Clivia hasn't aged well, or frost trolls are considered beautiful in Tamriel.