It's normally spelled "brah", bra being slang for "over the shoulder bolder holder".
Urban Dictionary
brah
This is the slang term for "bro" which is slang for brother..a slang inside a slang 8) THIS ORIGINATED IN THE STATE OF HAWAII! for those who think that it originated in southern california or where ever, your are miss informed. It is the pigeon (english-hawaiian slang) word that is used state wide in Hawaii not only by surfers but by all people born and raised in hawaii of all racial groups. and it pains me when i hear cali haole tourist say it.
#TheEducationOfBiggRed
Bagster