Determining a premature death of a brother or sister from a Horoscope

As we already know, the formula of premature death includes the formula of danger to life – 1/10 ~ 8 (damage of elements of the first and (or) tenth houses from the elements of the eighth house), plus an additional condition – damage of Mercury or 3 ~ 8 (Mercury and (or) 3 house of the horoscope is affected by elements of the 8th house or Black Moon).