What does it mean when a person that is dead apologizes to you in your dream?

The category of "dead person" is so vast that a meaningful answer is difficult. Generally speaking, during the period of mourning, it is perfectly normal to dream of the deceased. These dreams represent the dreamer's feeling of loss and sadness. The apology in this dream could express your own need to justify feelings of anger toward the deceased for their abandoning you. However, if the dead person is not a close relative or friend but a stranger or frightening apparition, the interpretation would be quite different. See the link below for further discussion.