A Will will simply give the name of the person making it, the fact that he/she is "of sound mind" what he/she wants done with his/her possessions and money (who is to get what), who the Executors are and who witnessed the signature of the person making the Will and the date the Will was drawn up and signed. There have to be two Witnesses to the Signature who cannot benefit in any way from the Will. A Will can give details of family such as "I bequeath x to my wife, son, daughter" etc., and give names and addresses of individual relatives but it all depends on individuals - in those days it was possible to exclude the whole family from inheriting anything, so if a person decided to leave his/her estate to a Cats' Home it would give no information about relations. You can only tell what information is contained in any Will by getting a copy, whether that is worth it or not is purely your decision.