The phrase "brother's keeper" means being responsible for the well-being and safety of one's siblings or close relatives. It implies looking out for and protecting them. Full definition
«For the umpteenth time, Dr Ahmed calls on communities in the state to be one another's brother keepers while reiterating his determination to guarantee peace and harmony in the state,» the statement said. (ghanapoliticsonline.com)
On Thursday, the Snowmass Free Concert Series continues with Brothers Keeper and John Popper on Fanny Hill in Snowmass Village. (aspenpublicradio.org)