Sometimes long passed relatives turn up in dreams; it doesn’t necessarily mean any spiritual presence happened, it could have been just another subject of a dream, a kind of brain animated “what-if.” I have sometimes dreamed that a relative passed away had never done so, and spoken with them as though that “revised history” was the factual state of affairs. Sometimes with even more pronounced revisions, such as a relative who died with Alzheimer’s never having lost her mind at all. I never asked any what life beyond the grave was like; that never seemed plausible in the dream.
Well, dreams are a mystery, just as out thoughts are a mystery. It is a great circularity to try to explain them. We do not know their source.