Rahu is a karmic shadow planet
Placement of Rahu in 12th needs to looked from the Zodiac, Mahadasha and aspects on it.
The primary thing that can be stated is linked to the individual finding their aspirational success away from the home/home state/home country.
Also, these individuals plan big and many a times be lost in their dreams till there is not strong Mars or Saturn to support conversion of dreams into reality.
You can read more on different combinations linked to astrology through the following links:
Quora Posts – Lateral Thinking
All the Best
For Paid Consultation – Link
God Bless!
Lateral Thinking 
Leave a comment