Edward (Jack Ging) has a slightly nutty sister, Amanda (Edith Atwater). He employs a nurse, Esther (Antoinette Bower), to look after Amanda. Weirdness ensues. This film was made in 1972 and not released until 1978. The film was released without a copyright notice and never registered for copyright. Because of this, it is in the public domain. This file was mastered from a good quality video tape master.
You can stream Die Sister, Die! (1972) free and legally on OldReel, via the Internet Archive.
Yes — it is in the public domain and can be watched and shared freely.