The pair had been in regular email contact about going to South Africa to visit Davison.
"Mum thrived on death ... it was the only thing that kept her going," Jonathan Westoby said from Auckland yesterday.
He said he was contacted on Monday morning by a Dunedin funeral home to say his mother had telephoned them about possible funeral arrangements.
Mr Westoby contacted his Dunedin-based brother, Simon, who found their mother in her flat.
St John was called, with staff later confirming her dead at the scene, and police were contacted.
The home was initially treated as a crime scene but her death has since been referred to the coroner.
A post-mortem examination was expected to be done today.
A service will be held at Gillions Chapel in Dunedin on Friday at 9.30am.