It happened around 8:27 p.m. on the 600 block of East Cornwall Street in the city's Kensington neighborhood.
Police say the 28-year-old victim was shot five times. He was taken to Temple University Hospital, where he's listed in critical condition.
The 24-year-old brother stayed at the scene and was taken into custody police said.
Further details on the dispute were not immediately released by police.
Anyone with information on this incident is asked to call police at 215-686-TIPS.