Sun in 8th house in Astrology, if exalted in own house gives long life, ability to take big loans from not just banks but family and in-laws. In-laws will be very supportive of the native if well placed. In Vedic Astrology, the Sun in 8th house is the home of wife and married life, giving a bright, positive light on that sector. If weak, then life can be cut short unless being aspected by a benefic planet like Jupiter.
The 8th house person rules the death and rebirth of a person or how one rises after a great fall in their life. This house also shows money through in-laws and friends as in loans you might get from them. Financial loans for home, business is also shown from this house. Deep-rooted issues of one's life and one's interest or lack thereof in the mystical world such as astrology, magic, tantric practices, ghosts are shown from this house. The 8th house also represents the life span of a person. This is simply the house of the occult. Secret affairs are also seen from this. Government taxes, spies, and business-related to secret government dealings are seen from the 8th house.
Death is not something to fear; you will die, you can't live forever, but if your lifespan is short (although it's a blessing in my terms), you can still extend it per Vedic astrology remedies.) We will talk about remedies later in the book. 8th house is a major(Marka House). This is truly a death-inflicting house, as the 8th house deals with things buried deep beneath the earth, and when certain planets align in the 2nd, 7th, and 8th house; it usually causes death for a person.
After marriage, a lot of readjusting is required. There is a separation of the family one was born in, and one's own stability and integrity are tested. It is a stage in life that can be very vulnerable. If one does things right at this stage, the foundation is in place for a long healthy life. This stage is a junction point of past and future, and the 8th house indicates Astrology for that reason.
The 8th house in Vedic Astrology corresponds to the lowest part of the trunk, the genitals, anus, and eliminatory system. Scorpio corresponds to the 8th house. Fixed, but ruled by the forceful Mars, add the signification of sudden calamities to the 8th house. On the positive side, the sharp and analytical Mars can also add an element of research to this house.
Sun in Astrology represents the soul. This can be read in the most flexible and general sense of the word. The word soul is used for the deepest and truest nature, for the ultimate sense of identity, inspiration, and aspiration. Sun in 8th house signifies one's essential attributes - the sense of self, ego, self-esteem, a sense of purpose, and so on. Energies and conditions that arise from the Sun's placement in a horoscope, along with the influences that the Sun receives, will be experienced in life as deep, long-term trends and processes that impact one's life as a whole.
Note: The degree of auspiciousness and inauspiciousness will depend upon a complete analysis of the horoscope (birth-chart).