She used that money for quite sometime to help out her mother and her half-sister. Didn't it stop sometime ago? Maybe with Leonida's death? I believe GD George is her godson and, since she is unmarried, perhaps the fortune (or whatever remains of it) will go to him. She, Countess Dvinskaya, wasn't Sumner Kirby's only child though, she had a half-sister Gloria. I don't know about any other nephews or nieces she may have that she may choose to leave money to--or give it all to charity.
She can be seen in various online photos--mostly at Bagration events. According to Marlene, there was a romance between her and her stepfather's nephew Prince Friedrich Wilhelm of Prussia in the 60s .