As per dream interpretation and meaning, dreaming of dead people means they have some unfulfilled wishes or they want to convey some important message to you. The dream is a warning sign. Dreams of people who have died is also an indication about some danger to you or some member related to the dead people in the dream.
Dream of people who have died and they had an unnatural death means they might have left something for you or want to you to complete some task so that they can escape from the earth.
Dreaming of people who have died who were really close to you and who cared for you means that you are on the wrong path with your activities or you are doing wrong things or are in a wrong friendship. They want you to change for the good.
People who have died also come in dream to tell you about their possessions and hidden wealth. They will show you signs about them. They also come to give clues about their death.
Dreaming of people who have died is a very common dream as people usually think about them or talk about them during the daytime and such dreams have no meaning. But if you are dreaming of them without any daytime influence then it has some important meaning.