who brought her provision each month and what did he get in return ?

The drover's brother brings her provisions each month. In return, he occasionally slaughters one of the sheep, gives his sister-in-law what she needs, and keeps the rest in return for the provisions.

"... his brother, who keeps a shanty on the main road, comes over about once a month with provisions. The wife has still a couple of cows, one horse, and a few sheep. The brother-in-law kills one of the latter occasionally, gives her what she needs of it, and takes the rest in return for other provisions."