Good question. I have a book written in the 1920’s by a noted Jesuit on the subject which seems to support disembodied spirits that are sort of stuck here. I have not had a chance to read it. It is however possible for satan and his demons to have knowledge of our own pasts and those around us and to appear to us as if they where the spirits of our deceased loved ones in order to lead us away from the truth, or even pose as a saint or an “angel of light” Which is a good reason not to run after every sser even one who proports that they are giving a message from heaven until the Church has made a FINAL judgement of the case.