Another version of the story at this link. Includes a map of the city with a mark showing where the shooting occurred (intersection of E 91st and South Woodlawn Ave) and says that each man had multiple gunshot wounds, father is in critical condition.
Aaaaaaaannnddd... here’s the link: http://abc7chicago.com/news/father-son-shoot-each-other-in-argument-over-who-would-walk-dog/1852752/