 His brother Manoah Sibly (1757–1840) was a linguist, as well as a Swedenborgian preacher.Under Manoah's name appeared texts including a revision of John Whalley's translation of the "Tetrabiblos", and a translation of Placidus de Titis; as an astrologer, Ebenezer is said to have used the Placidian system of houses; as a student of alchemy, he translated Bernard of Treviso (the fountain allegory).It has been said that experts of the time would have seen that Sibly was not very discriminating about the sources he chose, and drew on unpublished translations that he had borrowed.