When genealogists look at their ancestor's will, they usually pay attention to the witnesses. They should as those names can be clues. However, witnesses are not necessarily related to the deceased. They may simply be neighbors. An ancestor wrote her will in 1902. The witnesses were not relatives. When I looked them up in the 1900 census, the ancestor who wrote the will and the two witnesses were all enumerated on the same census page.
Just remember--the witness should not be named in the will. That's usually considered a conflict.