I've just gone back and searched my records and it seems that Henry Charles and Mary Bobart had another surviving sister, Charlotte Australia Bobart, born 1841 and died 1908. As far as I know she never married, and it's possible she raised Henry Robert Tilleman after his father's suicide.

Henry Charles was buried at Rookwood after his death, but later removed and re-buried in the Marsden plot at St John's Cemetery Parramatta, with his wife Mary. The graves of Henry Hodgkinson and Elizabeth Mary Bobart are marked with headstones, however Henry Charles' and his wife Mary's graves aren't marked.