Thanks for spotting the Spengler quote. I'd forgotten that, but it's utterly in character, and shares both his strengths and his weaknesses: that is to say, he's right to recognize the identity between late classical occultism and late modern occultism, and wrong to dismiss both movements as cavalierly as he does. As for your question, the astral body persists for quite some time after death. The first death, the death of the material body, starts the process of leaving incarnation; the second death, the shedding of the etheric body, usually happens a few days after that. That's when the real work of the afterlife begins, because the soul is then embodied in its astral body and mental sheath, and has to process all its experiences during life -- and this takes place on the astral plane, through the astral body. In the course of that processing, the astral body dissolves, its forces returning to their sources in the different sub-planes of the astral, but all its experiences are passed on to the soul and become part of the enduring knowledge of the individuality, the part of you that survives from life to life. Once that's finished, the dead person spends a more or less brief time in contact with the mental plane, and then descends into incarnation again, picking up new astral, etheric, and material bodies in the process.