The existence of brothers should be divined from either the lord of the 3rd or from the karaka of brothers or from the planets combined with Mars
If Sun and Mars are associated with the 3rd lord in the 3rd house, the native will be courageous
Bravery is indicated by the presence of Rahu or Ketu in 3rd, whereas the presence there of Mercury would indicate timidity
If the 3rd house is occupied by either Jupiter or Mars, the native will have brothers
Jupiter in the 11th will make one suffer from the elder brother. If Mars is in 11th and is aspected by Saturn, there’ll be no elder brother for the native
The presence of 10th lord in the 3rd results in the destruction of most rajayogas
If the 2nd and 3rd lords are associated, the native will be generous. If Saturn combines such an association, the native becomes a miser instead
If the 3rd lord is in a dusthana, brothers die. If benefics are also there in these houses, the deaths will happen later in life