Budh in a horoscope has a direct relation with Mama/Mousi or in short Mom's siblings. i.e. Budh is a KARAK or Governor of these people in one's horoscope.
Many charts I have seen, Budh badly placed -- their mama has some issues, it can traced even before the birth of these folks! :)
1. Budh in Moola nakshatra (Dhanu raashi) in the 8th house and wakri -- that too in 1st degree --- Mama/Mousi would have headache, Critical issues with legs and overall health issues.
2. Budh in last degree of Jyeshtha nakshatra (Vrushchik raashi) with Mangal and in 8th house -- It is also owner of the 6th house...Mama had a great issues in 2002, even before the birth of this kid (when Shani was in last few degrees of Vrushabh rashi directly opposite to this Budh).
3. Budh in 1st degree of MESH in the 6th house with Mangal and Shani...Mama brain issues/operations and even Mom had the same issues.
On the other hand Budh, well placed in Mithun drushti by Guru -- Mamas are doing GREAT. Even MP/MLA etc etc. Many examples of such cases where Mom's family and relatives are doing exceptionally well.
AND So on. Hope this helps analyse charts to upcoming astrologers and also folks visiting here (myself included -- Please pardon the abruptness of posts due to lack of time -- I am NOT an expert!! And I am not a humble person at all). :)
Please note that, it is NOT due to the horoscope something bad happens to Mama or Mousi! :) It is MERELY reflected in a horoscope. Rather, someone's horoscope could give very good dos/donts to their Mama/Mousi etc. We, Indians being so superstitious and so fearful -- tend to blame everybody else than ourself for our own situation. Rather, Mama/Mousi's past karma is reflected in the horoscope for every person. The nervous system of a person and structure/memory areas of the brain largely depend on the state of Budh...
And One more thing -- ALWAYS use Lahiri ayanamsha --- ALL other are incorrect !! Take it from me and save some pain and agony! :) (I read someone stating respected/GREAT B. V. Raman here -- but the Astrological magazine uses wrong Ayanamsh...Rahul Gandhi becomes Dhanu instead of Makar raashi due to this!!??) :)