8th house is concerned with Saturn and Mars. So Rahu in this house gives malefic effect. The native would spend money uselessly on court cases. Family life would be adversely affected. If Mars is benefic and is placed in 1st or 8th house or Saturn (benefic) is placed in 8th house, the native will be very rich.
Lal Kitab Remedies for Rahu:
Keep a square piece of silver.
While sleeping Saunf should be keep under the pillow.