Twelfth House is the house of losses. Saturn is the natural lord of Twelfth House. Rahu loves shortcuts and doesn't really like the portfolios of Twelfth House. Having said that natives who wish to settle abroad do benefit from having Rahu in Twelfth House. 

     Twelfth House rules over higher conscious and attaining moksha. Rahu doesn't care about spirituality or life beyond. Rahu's only purpose in life is shortcut to name and fame. Twelfth House also rules over research and Phd. studies. Rahu doesn't really care about education unless other planets are co-tenants. Twelfth House rules over monestaries and prison. Rahu loves doing illegal activities and in long run just might ensure that a person has to visit a prison or monasteries for necessary soul searching. If planets like Sun, Mars, Saturn or Jupiter also influence Twelfth House along with Rahu than marriage of the native is late or there is no marriage at all. 

     Twelfth House is the house of research. While Rahu traditionally hates studies its seen that if planets like Mercury or Jupiter are co-tenants than a person may well be a researcher. Rahu's expertise is poison, toxins and chemicals. A person with a supporting Rahu in Twelfth House could work in a major pharma or chemical giant as a researcher. There are many people who wish to migrate and settle abroad in foreign and exotic locations. Rahu in Twelfth House provides the right environment to migrate and settle in foreign exotic lands. Twelfth House rules over sex, bedroom pleasures as well as sleep. Rahu loves the forbidden and taboo activities. If other planets are favorable than Rahu just might push a native to experiment with his sex life. 

     Aspects of Rahu are generally the most troublesome. Rahu aspects the Fourth House, Sixth House and Eight House from its placement in Twelfth House. Fourth House is the house of mother and shelter. With Rahu's aspect its impossible for native to enjoy the unconditional love and warmth of a mother. Rahu's aspect on Fourth House makes it difficult to venture into real estate, farming or animal husbandry. Unless other planets help native may not have much affection for mother and motherland. Rahu's aspect on Sixth House is bad for health department. Its not possible for early diagnosis of disease. Long hospital stay and several medical tests are a possibility. Medical bills do impact savings. Rahu's aspect on the Eight House is bad for inheritance and court cases. If astrological sign is supportive than there can be sudden and unexpected inheritance or alimony in court cases. But generally reverse is true and native stands to lose all his inheritance as well as lose big in court cases. There can also be problems with income tax officials.

     Rahu's placement in Twelfth House is considered bad. But its great for those who wish to migrate and settle in foreign lands. Rahu also helps boost sex life in a favorable placement. But for others Rahu's illegal activities could show them prison time. Rahu's aspect deprives native of love of mother and its not advisable to buy land property in their name. Health suffers due to Rahu's aspect and finances also deplete due to expensive medical treatments. Rahu's aspect could mean sudden inheritance and alimony for few but for others its the opposite case. Natives are advised to pay their taxes on time to avoid troubles from tax officials. Also regular exercise, yoga and pranayam, eating healthy and staying away from illegal activities is prescribed.