‘Świętokrzyskie’s Castle’ by Colette Sensier

Klara Świętokrzyskie is a Polish widow living alone in London. Her son Josef is a sporadic visitor and her daughter Gabriela is busy raising her own family. Klara keeps to herself, but is far from lonely as she has an active life in MagiKingdom, a World of Warcraft-esque game.
As Wladyslawa, she wanders the corridors of her castle accompanied by her paid-for-IRL accoutrements, including a leopard: a gift from the divorced Bernard, who occupies the castle opposite hers and with whom she has struck up a friendship. They have much in common: Bernard has known loss – his daughter lives on the other side of the world – as has Klara, who has named her avatar after her other – deceased – daughter.
Bernard is also a secret: neither Josef nor Gabriela know of their mother’s second life. How they find out comprises the second part of the story, which incorporates family dysfunction, grief, the dispersal of the digital in the post– of a person’s death and the online afterlife that we unintentionally inhabit when we’re gone.

From Best British Short Stories 2016,  Ed. Nicholas Royle