The man has been identified as 34-year-old Emmanuel Butler.
The shooting happened at 815 East Allegheny Avenue shortly after 10:30 a.m. in the Kensington section.
Police say the incident began as a domestic dispute between the two.
At one point the Butler, who uses a wheelchair, fired the shotgun and his mother was hit.
Butler is charged with Attempted Murder, Aggravated Assault, and other related offenses.
The mother was taken to Temple University Hospital. Her condition has not been released.